From The TimeSplitters Wiki

Zeppelin is a blimp in which you fight in. You can also fight ontop of the Zeppelin. There are only three rooms. In each room, there is a fan in which if you walk over it, you'll be blown up to the next floor in that room. On top of the Zepplin, there is four fans. But if run run into them, to get cut up and explode.

Easter Egg

• On the Zeppelin in the Sky Lounges, the walls have little signs next to the ramps up to the Hydrogen Storage and Bomb Release. There is a mistake in the way that the signs are placed. The Bomb Release is in the middle, where the trapdoor is, and the Hydrogen Storage is the two big rooms that are at the end of the blimp (were Red and Blue Base is).

Another easter egg that is really of no use (or some) to you when you are fighting enemies; when you go out on top of the blimp you can walk into the propellers and completely splat yourself. Note that it is possible to make a bot walk in to it (Play as Gladiator and be the Gladiator, get the bag first in Bagtag (the bag is on top of the blimp), or get a whole team against you in Team Deathmatch, then reach the top of the blimp and stand on the propeller when your enemies come, although they may sometimes walk up any propeller you stand on).