Stuck at the water facility!
 

I don't know how to get into the place, is there a door, a rope somewhere?
There are still 2 bad guys alive inside and I don't seem to find the way to kill them from outside. I have tried with the binoculars, looking right and left and I see nothing, last night I was up till 3 trying to figure it out...

You aren't very specific, so I'm not sure where you're talking about. To get into Looten Duke's hideout you can break down the main door or go around to the right side and break a support on a pillar. The pillar will break and offer you a way to get inside. If there are only two guys alive inside, you might be talking about the two mortars after you've taken out the rest of the gang. If that's the case, you can kill them from a distance, or get a running start and double jump onto the roof from the elevated platforms. The jump is tricky, but it usually takes less time than killing them from afar.

If you're not talking about the Looten' Duke's hideout, you should specify. But if you are, I hope the above helps.

yeap, the door breaks all right
 

Thanks, I just keep on failing to notice elemental things