Resident Evil: Revelations

I'm stuck in episode 8 trying to escape the flood help?

I'm in episode 8. I'm under water, the boat is sinking/flooding. My objective is to escape the flood. I am at the part where Chris will send you a radio transmission about "not allowing the virus to contaminate the ocean" or something on the lines of that. Then I get to a door that I think I need to get through, the gold objective marker thingy is just on the other side. But the door will not open because its "too dented". I've kinda gotten stuck here. What do I do?

Swim around and look for open steel gutter doors in the ceiling. damn i'm not saying this right but on the ceiling there should be alternate paths to go over to that room.

You should find some metal tube many times because you will use it to remove or open the locked metal bars.Try watching its walkthrough on Youtube.