In the Quantum of Solace game for Nintendo Wii how do you find Greene in the hotel

you have to find magrano before he kills the girl. then you shoot the gas tank near magrano and he dies. then you go down stairs to that main room. there will be guys. then you kill them then go to the door and press the unlock (- button) and i wil explode. then greene will be upstaairs and you have to shoot the gas tanks near him. and avoid his gernades