lol when Desmond said there were diving suits, charlie was like "you go get them and i'll flip the switch" , I was litereally yelling at my tv "NOOOOO PUT THE SUIT ON FIRST AND THEN DEAL WITH THE SWITCH, YOU ARE NOT INVINCIBLE!!!"
I think because of Charlie's past experiences with Desmond's visions (Desmond saves him, and things turn out worse because of it), he had one or both of two things going through his mind:
1. Desmond had already succeeded in saving him, so there's no need for caution. As it's happened before, he didn't feel the need to second-guess himself.
2. He realized that doing anything differently because of Desmond's visions would have an adverse effect.
thats exactly what i was wondering..if it was a flash forward..why does jack speak as if his dad is alive?? is jack that far gone?
ABOUT JACK'S DAD (CHRISTIAN)
Sorry, I feel like people keep missing the discussion on it 
Here is what we know:
1. Christian has been seen on the island earlier in the show.
2. The scenes this week were post-island, not pre-island.
3. Cusaloff have said (more than once) that Christian is certainly dead (but he "may be using the word 'dead' in a sense we [the audience] don't fully understand yet." - unknown whether that was a serious comment or not).
4. There has never been an instance - or hint - of someone coming back to life on the show.
5. His body is in an unknown location.
Here are the different theories people believe:
1. He was never dead.
2. The island/Others brought him back to life.
3. The flash forward was a POSSIBLE future, which could be changed. In this version of the future, Christian is alive (unknown as to what changed for him to be alive).
4. Christian is dead, and Jack was making reference to the fact that his father was an alcoholic, but was never fired for it. (Or is delusional due to emotional trauma and/or drugs.)
I personally believe #4. I think this lines up with the looks on the doctors' faces. This also lines up with Jack not wanting the pharmacist to call his father's office.