Head back to operations where your teammates are, but be cautious because on your way you'll be attacked by groups of Xenomorphs. Take care of the first wave in the morgue, remembering to watch the ceiling and the walls closely. I don't recommend staying there for too long, though, because killing enough of them won't stop others from coming.
Once you're back in the main corridor, with the sentry turrets, move towards the other end, eliminating aliens on your ways. When you reach the barricade, turn right to enter the medlab.
Go straight ahead, then turn left to return to operations (if you get lost, use the motion tracker, which displays the destination). Attack the Xenos that are bothering your teammates. Try and find a wall or any other obstacle to put behind your back so as to prevent the aliens from performing a surprise attack.