WhiteDwarf: You're a jock. These guys are nerds. There's lockers in here. Do what nature says must be done

Maybe you can shoulder-check him into a locker? It'd give you some cover from the guy with the gun a little ways away.

In fact, if you remember to keep your katana's sheathe on-hand for this next part, you can kind of just...

Slam the dude in the gut with it with a quick turn. Yeah, that's a cool maneuver. Send him straight into the locker.

SecOfficer: flashbang spam.