Can't seem to finish Mission 10

I can't seem to finish Mission 10.It's getting really frustrating because even when I save to game it always starts from the beginning unless I get to the Security area!!!I DID get to a part where there was pole which was spinning around,but when I slowed time I couldn't figure out how to jump to the ledge.In fact,I couldn't even FIND the ledge!!!


Can somebody help me?

Is there a way to unlock ALL the missions without finishing them?


I should have known those alien maggots booby trapped this sub.