Guards in scp are quite stupid sometime in particular the guard who was sobbing in the bathroom thought there was an scp outside and committed suicide which was infact a dumb thing to do but to be honest i guess he didn't know what was outside but he did have a gun
The guy worked at the Foundation and probably knew that just shooting at most of the SCPs in the facility wouldn't do much. He figured it would be better to take his own life then let his neck get snapped by a hunk of rock or get shredded by an invulnerable creepy boi