Push the button to bring the lift down, and go through the door to enter the ship. Go down the passageway into the next room. An alarm will go off - kill the Mercenaries and push the two buttons, collecting the freebies lying around, then go back outside and step on the lift.

Go through the doors, kill the Mercenary. Jump from the biowaste tank on the right, climb out onto the ledge and kill the Mercenary working the controls.