I recorded it and the map on the door was one of the things I want to go back and look at. My first impression was that it indicated where all the Dharma hatches were, and that there was one in the middle (maybe a main one) surrounded by six or so others. If that's the case, I'm thinking the middle one may have been the one where Ethan took Claire.
The thing about Sun is, you peg her as the kind of person that would be honest, so in telling Jin that she had always been loyal to him she's telling the truth. And she's so likeable that you want to believe her. But the thing with this show is they leave alot of things open ended, that way they can come up with a plot twist later that just blows you away. But with Sun, we know that she was deceitful since she learned English behind Jin's back and was planning on disappearing. So I think it's entirely possible she did cheat with the other guy.
But this island experience has changed alot of people...it certainly changed Jin and I think she's fallen in love with him all over again. So if she did cheat maybe she felt that it would serve no purpose in telling Jin the truth, that maybe they will be stuck on this island for the rest of their lives so why ruin this one bit of happiness they could have together.
Just my two cents....Actually I have alot of "cents" about Lost because I am so freaking addicted to this show!