A time traveler approaches you, wanting to play a game. This time traveler has the ability to return to any point in the past with all of his accumulated knowledge, thereby changing the past (confirming whatever variety of branching-timeline time travel theory is implied by that, if any).

He proposes this game:

He will shoot you in the head, killing you instantly.

He will then travel back in time, to a point before shooting you (but after you decided whether or not to play the game).

He will then give you $1000000 and leave.

If you were to decide to play the game, how likely are you to survive?