From The TimeSplitters Wiki

Fire Extinguisher
NEEDS IMAGE
Ammo	18 seconds of foam
Fire Rate bullets per sec/cartridge time	Continuous stream
Reload Time	N/A
Damage (per Single Shot) Head/Body/Leg	None
Type	Other
Zoom	No
Primary Fire	Shoots foam
Secondary Fire	Shoots foam
Games	TS2

The Fire Extinguisher is a nonlethal weapon used to put out fires. In TimeSplitters 2, it appeared on the 1990 Siberia level and the 1972 Atomsmasher level, where it is used to put out fires to open fire doors.

To extinguish yourself, aim forwards and walk while firing, or aim toward your feet and fire. In Arcade Custom, bots will use the Fire Extinguisher to attempt to kill you. Some players have been known to obtain Longest Innings awards by setting all weapons to fire extinguishers then using their fists to kill the practically defenseless bots.

If a bot is lit on fire while holding only a fire extinguisher, a funny sequence begins where the bots stands in one spot, rotating 90 degrees in every direction with the fire extinguisher pointed at the ground. They don't attempt to put themselves out, and the pattern continues until someone either puts the fire out or the combusted bot dies.