Feb 29, 2020
No kidding...
The vent is... barely even big enough to accommodate a small person in the first place. And why in the gods would anyone go to that trouble just to go to the classroom? Hypothetically speaking, with a murder weapon... on their person? Good luck getting out the other side without being seen as you struggle, potentially mortally injuring yourself in the process. And that’s assuming you can even fit.
I mean, may not be a complete impossibility, but that’s an... awful lot of fixation on a tiny, cramped space when other, much less clumsy methods would suffice at the freakin 11th hour.
Considering you would have to find your way *UP* the vent shaft as well...