Who are the soliders? Why are they trying to capture the guys? Why have they left the guy who'd been there 40 years alone? Why are there people imprisoned at the base? How long have they been there? How did the girl end up pregnant? (Don't go there. Sickos.) You need to answer these kinds of questions before you're going to get anywhere. Unless you have reasons for things to be happening, it's just a mindless stream of events, and not a particularly interesting one.
Perhaps some government is conducting top secret experiments on the island? The prisoners are scientists being held against their will and forced to do the research. The soldiers are trying to kill the guys to prevent them from giving away the location. And the old guy could be secretly working for the soldiers and betray them. They're thrown in with the rest of the prisoners, then they and the girl escape and have to evade capture and find a way off the island. Could be interesting.
Only thing I can't make work is the pregnancy. I'd get rid of it.
With all due respect Noodle, I don't want you here. - Ratboy Productions