School Shooting and a Suppressor

My friend was a victim of a school shooting once, but he couldn't tell if they were in the library because of the suppressor on his AR.

Explanation

This is a dark and morbid joke. It plays on the idea of school shootings and the use of suppressors on guns, which makes them quieter. The humor comes from the absurdity of someone being shot and not knowing where the shooter is because the gun was too quiet.