EXCELLENT finale, although Charlie's death pissed me and my wife off considerably. It just didn't make sense. The only reason I don't buy the "Charlie knew he had to die, so he sacrificed himself" excuse is because 2 seconds earlier he was ready to walk right outta there and live. He even said "so much for fate" as he was walking away from the control room. What happened between then and the incoming transmission/grenade that made him do a total 180? That was just lame. They should have made the metal door shut automatically when he entered the code or something, like a safety measure (kinda like what happened in the island hatch when the code went un-entered). That would have been a more appropriate way of killing him off in my opinion. The fact that such a likable character died needlessly really ticks me off. AND, if we come to find out that he only sacrificed himself so his pals could unknowingly contact MORE BAD GUYS, that makes it even worse.
Other than that, I loved the episode. Best 2 hours of TV I've watched in ages.
p.s. I'm with IM--- I thought the 'code' would have been "the" numbers.