Ok after rewatching the episode (I could watch it with some sanity because I knew what was coming)
I realized that there is absolutleley no way that he is dead, I'm sorry there's just not.
my reasons
1.) she gave him something to drink seconds before he flat lined
2.)Jack said that "I'll do anything to help the both of you" and then they were giving eachother wierd looks
3.)Jack, Marshall, Wiess and Dixon were planning this huge escape plan for vaughn. Its not like Monica& Allison to put that in if it didn't have any meaning.
3.)She didn't look nearly sad enough she looked more sad when she found out he was married than when he died and I know JG is a better actress than that
4.)JJ Abrams said "The vaughn story ine is not what it seems"
5.)After all that, after "We'll find eachother we'l always find eachother" after "What it comes down to is faith" after The seemed to have a bond that even death could not severe" AFTER 4 YEARS OF GREAT ROMSNCE SCENES AND SWEET LINES why would they kill him off therre is just no possible way.