I really liked this episode, but one thing that puzzles me is why Jack chased after Desmond into the jungle. Of course, he wasn't looking for the code, and he didn't believe anything would happen if it wasn't typed in. He also wasn't eager to admit having met Desmond or to talk about his wife. So why did he go after him?

He was in a very distraught state, he wanted some closure on why the hell Desmond is on the island anyway and didn't know any other way to find it. If Desmond disappeared so would any hope of that closure.

I think a little of Jack may believe Desmond and the film, but the rest of him is in a state of denial. So, maybe something was drawing him to Desmond to figure out what's going on. And then when Desmond told him the numbers, he figured he should go back, just in case and maybe also to test his own belief.

I really liked this episode, but one thing that puzzles me is why Jack chased after Desmond into the jungle. Of course, he wasn't looking for the code, and he didn't believe anything would happen if it wasn't typed in. He also wasn't eager to admit having met Desmond or to talk about his wife. So why did he go after him?

I think plain and simply Jack just wanted answers. He wanted an explanation.

I think plain and simply Jack just wanted answers. He wanted an explanation.

My thoughts exactly.