i am stuck on the part where i have to go by the train and kill the guys get a keycard and then go into this place n snipe like 5 ppl. then some more guys come n i tried grappling them but i allways get seen n killed!!!!!! ne1 plz help me its sooooooo annoying. PS. its after the level where u get on the boat, hhhhhheeeeeeellllllllpppp!