I watched that clip with the map a few times, and I'm trying to figure out if it's a projection from somewhere around the black light, or if it's been drawn on the door itself.
I think "Henry" knows more about the hatch than he's letting on. He remembered those numbers far too easily - even after falling and getting the wind knocked out of him. I get the feeling that he was yelling "What's happening??!!" etc during the loudspeaker sequence to distract Locke and keep him from figuring out what was being said over the loudspeaker. Notice how he tried to caution Locke about scooting under the lockdown door - as if he knew that the toolbox wouldn't be strong enough to hold the door up for the length of time needed to slide under it. And then his comment afterward: "It's your hatch..."
During the time that Locke was stuck under the door, it appears that Locke gave him information on how much they knew about the hatch. Big mistake!!