Level 15: Sorry Don't Make it So
This level can be as long as you wish to make it. The fastest approach is just to begin running down the corridor.
Keep running until you reach the end of the corridor and an open door. Run in through the opening and up the stairs opposite. At the top of the stairs jump to your right, so that you will fall into the Alien Goo. Swim to your right and down the corridor. As soon as you get to an opening get out - you should have a bit of energy left.
If you swam far enough you should be in one of these three areas. If not, then you have some exploration left to do.
This is the exit terminal. There's a 2x recharge near by so if you're low on power you may want to top it up - but beware, you will have to swim for it!