The Looking Glass Hatch

As we can see here The Looking Glass map says it's a 'Submarine Port'. The DHARMA Iniative must have docked the submarine here to access this hatch.

Now as far as the two females down there, they must be others. Ben has demonstrated time and time again, how he wants the others to stay here, on the island. The submarine was hope for them to leave if they wanted. Jacob is how he controls them into following his own agenda. So it is very clear he lied to them about the hatch being flooded. After sending two or more down to The Looking Glass, Locke unfortunately blew the bloody thing up dooming the people down there.

And now for my findings.