From The TimeSplitters Wiki

Time Assassin Cortez
Unlocked by	Beat "What lies Below" on Normal
Species	Human
Size	Normal
Accuracy	N/A
Agility	5
Stamina	5
Fire Proof	5
Shock Proof	5
Default AI	4
Native TimeZone	1924-2401
First Appearance	TSFP Story Mode
Relations	Cortez
Games	TSFP

TS1 Gesture	N/A	TSFP Gesture	Bows down at screen and says "Shhh! Mum's the word."
TS2 Gallery	N/A	TSFP Gallery	Black with buckles, leather straps and a hood! How cool is that? Bound to impress the chicks unless, of course, you get the eyehole misaligned and trip over a coffee table

In order to enter the warp hole in 1924, Cortez had to disguise himeself as a Time Assassin. Once he reached the future he provided cover for his past self, then re-entered the wormhole back into the past to destroy the Time Crystals.