Of course, everything Arthur had just deduced could be completely wrong. It's not a given that Martin chose his seat; what if all the other spots were already taken by other students, leaving only the front-row seats for Martin? This is entirely possible if the seating in the class isn't fixed.
That's why Arthur looked even deeper into a few more details.
Because his observation time was extremely limited to avoid arousing suspicion, and his field of view was only through the small glass pane on the classroom door. Not to mention, the janitor at this school didn't seem very diligent, so the glass wasn't cleaned very well, and it was also quite scratched. All of these factors significantly reduced what Arthur could observe.
Normally, when observing and analyzing, Arthur would look at a person's overall reactions, especially their facial expressions and eyes. But due to these limiting conditions, Arthur could only redirect his focus to other things with a lower predictive accuracy, such as the hands.
Or, more accurately, hand movements.
If Martin was uncomfortable with his seat, he would likely show corresponding signs, not just on his face, but here, it could be his arms. For example, Martin might keep his hands clenched, or hold onto something. These can all be understood as defensive reactions when threatened. The act of clenching or holding something is partly a primal instinct to claw when in danger, or more specifically, when in danger, people will subconsciously grab something to use as a weapon for self-defense.
At the same time, this behavior also serves to distract the person's own attention, reducing their apprehension toward factors that they are consciously aware won't harm them, but they still worry about.
Next is body orientation.
This might sound a bit abstract and uncertain, but in a situation with limited information, Arthur could only do his best to filter out plausible information from general patterns.
Body orientation can be understood as, when a person is not too restricted in how they sit, they will tend to "point" themselves toward the area they feel most at ease with. The clearest manifestation is in the legs, and then from the hips up. For example, Arthur once saw a man who was cheating on his girlfriend, so when they talked, the man would unconsciously orient his body's center of gravity away from his girlfriend's position, only turning his head to chat. This happened because of a sense of unease and a fear of being discovered by his girlfriend.
Meanwhile, the place he oriented his body towards was the exact location of his phone, which held his connection to the mistress he was dating. It was also the thing that made him feel at ease compared to the girlfriend he was deceiving.
Applying both hand movements and body orientation to Martin's case, if he was uncomfortable with his current seat, Martin would have to show corresponding signs.
This may sound long, but it happened in just a few blinks of an eye. In the first second of observation, Arthur analyzed Martin's seat. In the second second, he analyzed Martin's behavior.
And the result was quite surprising to Arthur.
Martin showed no signs of discomfort at all; if anything, it seemed like he wanted to be in that very spot.
Martin's hands were completely relaxed, with his fingers loosely extended. Meanwhile, his body orientation was not toward the blackboard in the front, the inanimate object that should have made Martin the most comfortable after being pushed to the front-row seat.
Based on the angle of his knees, Arthur saw that Martin's body was oriented towards a rather unexpected location.
It was the teacher's desk.
Why would Martin feel at ease with the teacher?
Someone like him should usually be quite disconnected from the relationships around him, shouldn't he?
A question arose in Arthur's mind. He felt as if he was grasping some key point.
However, the observation time had now reached the third second, which was starting to get "too long" for a parent just observing the school's facilities. So he just kept this question in his mind, pulled away from the door, and continued walking with the principal.
What he didn't notice was that, right after he left, the teacher in Martin's class glanced toward the door where Arthur had just been standing.