Ah..That part. Took me several tries. When you reach the door before entering and they say you have 2 minutes remaining, you have enough. When you enter, instantly send one of your squad to the control panel while you snipe out all the turrents while sending your squad to plant proximitys on the cylinders. I finished it with 1 second before the explosion. Scared me crapless. I remember my frustration when i reached the end but the counter kept on ticking while they talked for 4 SECONDS.