Watch out for asteroids.

12. Escape.
Make sure your shield is on, then take the Big Sphere Room tube up
to the surface; head for the Icarus.

The Marine's logbook has the information you need to get in the door.
The battery Gen gave you will activate the Icarus if it's still three-fourths
full. Pick up your old one and use it on yourself to swap out Gen's
battery, then step over to the nose of the Icarus. Insert Gen's battery
and enjoy.

And if anyone found a medical code, please let me know...