This already happened on Angel. I *heart* David Boreanaz!
"A normal paralegal in a typical law office on an average day, Henry didn't think anything was strange when the lawyers threw boxes at her and screamed for raw meat. Even the bloodstained shirts and screaming secretaries didn't seem terribly unusual. And yes, it was a little odd that Edward John Johnson tried to eat her face, but he'd always been touchy-feely. Henry wasn't alarmed until she saw something so disturbing, so implausible, that she nearly became paralyzed with shock. The bloody, twitching lawyers, who had already eaten most of the support staff, were putting papers into files. Yes, she and the other survivors realized, this was the apocalypse, and they were going to be eaten by the swarm of lawyer zombies driven by their bloodlust to eat live flesh and reorganize files. Now, maybe, just maybe, if they can make it to the service elevator, an elevator the lawyers don't know exists because it is a functional part of the office, they can escape. But if they are going to die, by god, they're going to take some lawyers with them. This is a horror-comedy that is more than happy to hack and eat it's way through zombie lawyers and obnoxious office staff to reach the elusive service elevator."
At least this one pokes fun at itself.