What do I do on Level 4

Hint 1 of 4:

Look at the blueprints.

Hint 2 of 4:

You should notice that there are barracks here for sleeping.

Hint 3 of 4:

There is also something of interest in Docking Bay #3.

Hint 4 of 4:

It's just a spool, but you it could come in handy.