[SPOILER ALERT, DO NOT READ UNLESS YOU WANT TO]
http://lost.cubit.net/pics/2x17/blastDoorMap.jpg
ok, so if you read it, it says "I am Here" so that must be the hatch, the other places are the other underground bunkers. I think the electromagnetic generator is in the middle, and that the x's that cut off the bunkers from the middle are where they have been sealed off, like the concrete in the hatch that blocks the one door. Does anyone remember what symbol was in the hatch that the other plane survivors found? Like, the hatch on the map has a swan on it, because that's the facility name, what was the name or symbol in the bunker where Eko found the bible with the film reel?