I have an idea.
The nerd should've went around having trouble and everyone just wanted to help him out, but then he keeps messing up everything for the classes and they still try to cope with him. This eventually gets all of the classes killed (The Spy ends up running out of cloak in the middle of the battlefield from talking to the nerd for to long. The Heavy gives his sandvich to the nerd and then the nerd finds a medic for him which turns out to be a spy. The Engineer sets up a sentry to protect him, and then the previous spy comes back disguised as an engineer and gives him a bunch of sappers, then tells him to place them on all of the electronics in his base to make them better.etc), and then they all switch to the Blu team so they can kill him. XD