GTA IV Out of Bounds glitch 

My brother was driving around in GTA IV and for some unknown reason he ended up out of bounds. When he got the car he started falling down and when he gets to the bottom he just goes back up. Now Niko is stuck going up and down like a yoyo lol.
Can't use cheats or weapons to kill himself, now he has to reset lol
This is the PS3 version