i hope im thinking of the right mission cause i dont know the names, but if its the one with the ballas and the shooting at the start is in a warehouse, then i think im right.
just dont loose all your life at the start and when you get into that office, kill the guys in there and then run full sprint after the russian but instead of shooting him run out to where the bike is and his car, a banshee i think, now just get in the car. because you get in the car for some reason he wont get in and he wont take the bike either, he'll just stop dead in his tracks. now just get out and kill him.
you should make it by the guys outside, cause the ballas' aim.......SUCKS, hopefully im thinking of the right mission or else i've just made an idiot of myself.
good luck