[Seto Completed] [AI Mystery Manga] Episode 30: Why was the pulse of the man who ran up seven flights of stairs 72? | The Pulse Meter Uncovers the Alibi of "Mere Breathlessness"

監修者 Commit Ginza
Kenji
Appraiser, this time the alibi is "shortness of breath."

A rare chronograph for doctors disappeared from the exhibition preparation room on the 7th floor.
Immediately after, Takizawa, the setup manager, burst out of the emergency stairs, saying, "I ran up all the way from the 1st floor to the 7th floor."
Appraiser
I see. Then the person to ask isn't him.

It's his pulse. He can fake being out of breath, but numbers don't play along.
Kenji
Please don't measure my shortness of breath either.

Just going up the stairs at the station makes me look like I'm at the Olympic qualifiers every time.
CASE FILE 30 The Seventh Floor and the Alibi of Shortness of Breath
  • Incident occurred: 8:11 PM, a rare chronograph for doctors disappeared from the exhibition preparation room on the 7th floor
  • Before the event started, only authorized personnel could access the 7th floor
  • The elevator was temporarily out of service for inspection
  • Around 8:12 PM, setup manager Takizawa appeared from the emergency stairs and testified that he "ran up all the way from the 1st floor to the 7th floor"
  • Takizawa said, "My heart is pounding," while breathing heavily
  • At the same time, a chronograph with a pulse meter, used for exhibition explanations, was on Takizawa's wrist
  • Three people were present at the scene

① Three Suspects. Only the "Tired Man" Had a Showy Alibi

Suspect A: Koichi Asaoka 38 years old,搬入staff Receiving cargo at the 1st-floor loading dock from 7:55 PM. Carrying large material boxes.
Suspect B: Aya Moriya 34 years old, PR Manager Pre-checking live stream in the 7th-floor lounge. Smartphone recording data available.
Suspect C: Koichi Takizawa 42 years old, Setup Manager Possessing a service key. Strongly claimed, "I ran up from the 1st floor to the 7th floor."
Kenji
But Mr. Takizawa looked really exhausted.

That was the face of someone who had run up "life," not just "stairs."
Appraiser
His face might be that of a great actor.
But his pulse doesn't read a script.

② Takizawa's Testimony: "I Ran Up from the 1st to the 7th Floor Without Stopping"

Takizawa's Testimony: "Since the elevator was stopped, after finishing the material check on the 1st floor, I ran straight up the emergency stairs to the 7th floor. My heart was pounding when I arrived, so much so that I measured my pulse with this watch."
Kenji
To visualize one's fatigue with a watch, he's a health-conscious culprit... or rather, a person involved.
Appraiser
That one word is fatal.

If he "measured" it, then what it showed also becomes evidence.

③ The Pulsimeter Reads the Pulse per Minute from a "Fixed Number of Beats"

Appraiser
Kenji, the pulsimeter isn't a scale to measure speed.
It's a scale to measure your heart rate.
Kenji
Its name sounds gentle.

It's the kind of watch that asks, "How's your heart feeling right now?"
Appraiser
Generally, you count 15 or 30 beats and then stop the chronograph.
The scale on the outer ring then tells you the beats per minute.
Start counting pulse → Stop at 15 beats → Read heart rate

For example, if 15 beats are counted in 12.5 seconds, it's 72bpm
The pulsimeter quickly performs this conversion on the dial
Clue 1: Pulsimeter Basics
  1. Start the chronograph the moment you begin taking a pulse
  2. Count the number of beats indicated on the scale (e.g., 15 or 30 beats)
  3. Stop at the last beat
  4. Read the heart rate per minute from the outer scale pointed to by the central second hand

This is a feature found in classic doctor's chronographs, characterized by its ability to convert pulse rate from short measurements.

④ Takizawa's Watch Showed "72"

Record Remaining on Takizawa's Watch
Watch Used Chronograph with pulsimeter for exhibition explanation
Takizawa's Statement "I ran up to the 7th floor with all my might, and my heart was pounding, so I measured my pulse."
Chronograph Stop Position Pulsimeter display at 72bpm
Number of Stairs Approximately 132 steps from 1st to 7th floor
Appraiser
72.

At least for a pulse right after "running full-speed to the 7th floor," it's quite calm.
Kenji
72 is like the face I make when I'm watching videos on the sofa eating potato chips.

If I ran to the 7th floor at full speed, the bag of chips would fly.

⑤ "Breathing Heavily, Yet Pulse is 72" - Numbers Don't Keep Up with the Acted Fatigue

Appraiser
Of course, heart rates vary from person to person.
They change with age, physical condition, tension, and caffeine.

However, it's unnatural for someone who ran non-stop from the 1st to the 7th floor and was breathing heavily immediately upon arrival to measure a pulse of 72.
Why 72 is Unnatural
Condition Typical Pulse Rate Guideline Impression
Resting Around 60-90 Calm
Brisk walk/Light stairs Around 90-120 Slightly elevated
Quickly climbing multiple flights of stairs Often exceeds 120 Clearly out of breath
※These are just guidelines. This is not a medical judgment, but is being compared with the individual's testimony of "running with all their might" and "measuring right upon arrival."
Kenji
So, Mr. Takizawa's breathing was like a stage actor's, but his heart was working from home, right?
Crucial Clue for Readers:
Takizawa stated that he "ran up from the 1st to the 7th floor with all his might and measured his pulse immediately upon arrival." However, the pulsimeter showed 72 bpm. This is unnatural for someone who just ran intensely up stairs, making it highly probable that he only faked being out of breath.

⑥ Checking the Alibis of the Other Two

Records of the Other Two
Koichi Asaoka Continuously shown on surveillance footage at the 1st-floor loading dock. Receiving cargo from 8:10 PM to 8:14 PM.
Aya Moriya Recording a live stream test in the 7th-floor lounge. Video and audio continuous around 8:11 PM.
Koichi Takizawa Self-reported from the emergency stairs side only. In a position to freely use the setup linen cart.
Kenji
Mr. Asaoka was fixed on the 1st floor, and Ms. Moriya was recording on the 7th floor.

Only Mr. Takizawa's testimony is of the "trust my lungs" type.
Appraiser
And there's a possibility that he was over-acting with those lungs.
If so, the watch's destination should be nearby.

⑦ Crime Reenactment - Takizawa Ran Up Only "One Floor," Not "Seven Floors"

Takizawa's Actual Movements
  1. Takizawa took the rare chronograph from the exhibition preparation room on the 7th floor
  2. He immediately hid the watch in a linen cart on the 6th-floor service path
  3. After that, he regulated his breathing on the 6th-floor landing, biding his time
  4. He forcefully ran up only one floor, from the 6th to the 7th floor, via the emergency stairs
  5. He burst out of the door, exaggerating his heavy breathing, claiming he "came from the 1st floor to the 7th floor"
  6. He further said, "My pulse is amazing," and explained he measured it himself
  7. However, the watch showed 72bpm, which is unnatural for someone who just performed strenuous exercise
Appraiser
He didn't run seven floors.
He ran one floor and made a face like he ran seven floors.
Kenji
That's like lip-syncing in the stair-climbing world.

He's making sounds, but it lacks the live feeling.

⑧ The Missing Chronograph is Found in the Linen Cart

Linen Cart in the 6th Floor Service Corridor
A rare chronograph wrapped in a protective cloth was found under a pile of white towels. The protective cloth had fibers identical to those from the exhibition preparation room tray, and fibers from Takizawa's gloves were also confirmed on the cart's handle.
Kenji
There it is.

The watch is waiting under the towels as if it's waiting to be laundered.
Appraiser
The shortness of breath was an act, the prop was the linen cart.
The backstage is all set.

⑨ The Culprit is Koichi Takizawa, the Setup Manager

Your Heart Didn't Run Seven Floors

Appraiser: "Mr. Takizawa. You took the watch."

Appraiser
You said, "I ran up from the 1st to the 7th floor with all my might and measured my pulse immediately upon arrival."

However, the pulsimeter showed 72.
That is unnatural for a value immediately after an intense run.
Furthermore, the watch was found in a linen cart on the 6th floor.

You stole the watch on the 7th floor, hid it on the 6th floor, and then ran up just one floor to make it seem like you had been "downstairs the whole time."
Takizawa's Confession: "When I showed photos to an overseas buyer, they said it would be a considerable amount. The building was bustling due to the elevator shutdown, so I thought it was now or never. I thought if I looked distressed, no one would think 'he was on the 7th floor just now'..."
Kenji
He tried to create an alibi for seven floors, but it got returned with a 72.
Appraiser
He could fool with his breathing, but his pulse rate wouldn't go along with the act.

⑩ After the Incident, Kenji Attempts an "Extreme Exhaustion Appeal" by Climbing Just Two Floors

Kenji
Appraiser, I just went up from the 2nd to the 4th floor for verification.

I can't go on. This is my life's turning point. Measure it.
Appraiser
146.
You're genuinely exhausted.
Kenji
That's good.

My shortness of breath was genuinely backed up.
Appraiser
(In Kenji's case, rebuilding his physical strength might be necessary before recreating the crime...)

Conclusion: The Pulsimeter Uncovers Whether the Pulse Was "Really That"

Appraiser
A pulsimeter is a scale designed to count a fixed number of beats and read the beats per minute from that time.

In this case, Mr. Takizawa stated, "I ran up from the 1st to the 7th floor with all my might and measured my pulse immediately upon arrival."
However, the watch showed 72 bpm.
This was unnatural for a reading immediately after an intense stair climb, indicating the possibility that he merely feigned being out of breath.

Furthermore, the missing watch was found in a linen cart on the 6th floor.
While people can make distressed faces, numbers don't always play along with the same act.
What We Learn About Pulsometers from This Case
  1. Count and stop at a fixed number of beats: Use according to the dial design (e.g., 15 or 30 beats)
  2. Can convert pulse rate in a short time: A typical use found in doctor's chronographs
  3. Not absolute proof on its own: Due to individual differences and physical condition, it's important to combine with testimony and other evidence
  4. Key point this time was "contradiction with the person's explanation": The unnaturalness of 72bpm immediately after a full-speed run was the key
  5. Different from a tachymeter: A tachymeter measures speed, a pulsimeter converts pulse rate
Function What it counts What it reads
Pulsimeter A fixed number of beats Beats per minute
Tachymeter Elapsed time over a known distance Average speed
Telemeter Time difference between light and sound arrival Approximate distance to the source
※The pulsimeter is a conversion scale on a watch and not a medical device. Pulse rates vary significantly due to constitution, age, exercise habits, tension, caffeine, and physical condition. In this story, we examine its consistency with the testimony "measured immediately after running all the way to the 7th floor at full speed." The incident, characters, facilities, and watches are fictitious.
Key Deduction Points for This Case
  • A pulsimeter is a function that quickly converts a fixed number of beats to beats per minute.
  • Instead of judging "looked exhausted," we check if "the numerical value matches the situation described by the person."
  • 72bpm conflicted with the testimony of running seven floors at full speed immediately beforehand.
  • The crime is proven by combining the pulse rate data with evidence of hiding places and movement routes.
NEXT CASE
Episode 31: Whose Morning Was the 3 AM Call?
~The GMT Hand Exposes the Lie of "On an Overseas Business Trip"~
  • The suspect claims, "I can't go to the scene because I'm overseas right now."
  • However, the watch's GMT hand was pointing to a different time zone.
  • The second time display betrays the whereabouts of "the man who should have been overseas."
Next time, Kenji tries to claim he's internationally savvy just from jet lag!
※The reading and time difference settings of the GMT hand vary depending on the model. Next time, too, we will deduce by combining multiple pieces of evidence.

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