I just started to find my way through the crysis universe and encountered my first problem, I cannot find any enemies in that level any more! After clearing the landing zone I proceeded along the street to the harbor, cleared the area, but the submarine is closed. Then I went back to the beginning of the level, but there are no enemies left. Obviously I missed one action to trigger the submarine to open...? On my run I did not destroy the helicopter, just drove by. Is that it? So do I have to restart the level? Any idea?