Suffice to say, Jack is pretty hard to keep up with. You just never know when he's gonna pop back up in the Doctor's life and in Series 4 he returned to aid the Time Lord in his climatic battle against Davros and the Daleks and it was to be a particularly momentous encounter for the Captain. After all, Jack would never have been brought back to immortality at all if he hadn't been killed by the Daleks back in Series 1 of Doctor Who so it was fitting that he once again came face to face with the ones that had started it all. He obviously hadn't learned his lesson, though, as he attempted to shoot one - the Supreme one, no less, which was just plain stupid - and it promptly returned the favour and exterminated him on the spot. Ah, well. It was a worth a try. Always one step ahead of the game, Jack used his death as a decoy and managed to avoid another untimely death by incineration (with his clothes unharmed, which was rather impressive) to continue his mission to overthrow Davros and his almighty Dalek empire. Amen to that.