From the look of it, this floor doesn't have the elevator buttons.
I guess that when the door closed, it became a sealed coffin, suffocate anyone inside

You also can't see that "this floor" is just a small chamber with the elevator doors open.

If you look closely, there is a faint outline of the victim on the first panel's left-corner (if you cant see it, turn screen's lightning to higher brightness)

FJH said:

You also can't see that "this floor" is just a small chamber with the elevator doors open.

I would guess it's light blindness. Like looking out at night from a lit room, your eyes aren't dilated so it's hard to see very far.