i watched this movie when i was 13, what was it?

i remember something about all these people being killed in a hotel. i remember in the end he finds the key for the last room, it was buried in the dirt for some reason, idk. and i remember in the end it was just a crazy guy who had extreme schizophrenia, and he was each of those people. they reveal this when he's in some sort of armored car. he kills the drivers and i don't remember much else.

it must have been around 2002/2003.

please i know it's not much but please try. i would try IMDB (IMBD, i get it mixed up) but really what would i search? btw i did try.

and yes i tried google!

please help!