In the aquis level you have to power up all these filters. so you should
be in a place with dark, dirty water. you'll have to fight some evil
undines so get them out of the way. you'll then see these tentacle
plants, when you swim by they will try to get you but stay near the
ground and they wont be able to reach you. when your past them you'll
see a gate but the power isn't on so the door will not open. if you look
up you should see an entrance into a room, that room is the engineering
room. when your in the engineering room there'll be a map in front of
you. on top of the map there is a button. this button is the button that
opens a huge door that you would of seen when you first swam into the
bay. go into that room (there are no guards in there) and this is the
power plant that you need to operate the doors etc.