Aliens: Colonial Marines/The Raven

Part 1
In the beginning of this mission, you have no weapons or motion tracker. You will only have your head-lamp light. Look for the glowing hatch on the floor and press the use button to open it. After that, quickly head down into the hatch before the big alien returns. traverse underneath the floorboards, but do it slowly and cautiously because the big Alien will burst through some of the open areas in order to grab you.

You will then come across a makeshift ramp out of the floor. ...