There was a bug that allowed you to get back up into the ventilation duct through which you enter the level (in single player mode). You have to go into the bathroom stall, crouch on the toilet, and spin around a few times IIRC. Once you're up there, no one's getting you out until you run out of ammo.
haha, I def remember having a "no oddjob" rule. And if you did pick oddjob, lord have mercy, cuz everyone was comin after your ass and nobody else! For whatever reason, I would irrationally target anyone playing as boris as well...