Turns out Pascal's mugger is real, and as would be expected of someone who does Pascal's muggings, he's a jerk and likes forcing people to make impossible decisions. Also, his threats are discovered to be truthful and credible. He decides he's sick of mugging after collecting a few trillion dollars from it and wants to try something new. He takes out a gun (killing people with Matrix powers is for cowards) and forces you to make a choice.
Scenario 1: He puts the gun to your head. "I will kill you unless you let me put you through torture 3^^^3  times more intense than anything you can possibly imagine. Don't worry though, it'll only last for a millisecond, and you won't remember it or suffer any trauma or anything."
Scenario 2: He puts the gun to a random stranger's head and tells you to make the choice for them. He freezes the stranger in place with his Matrix powers (2a: the stranger overhears before being frozen and decides on what they would choose, 2b: the stranger is frozen before they know what's happening) so the stranger has no way of communicating their preference to you. He will shoot if you don't make a choice.
Scenario 3: He puts the gun to a random stranger's head and tells them to make the choice. After you hear the stranger's choice (3a: they choose death, 3b: they choose torture), the mugger gives you the option to override it. He will abide by the stranger's choice if you don't make a choice.
What should you do?
In the words of the Torture vs Dust Specks question this was inspired by: I think the answer is obvious [in all scenarios]. How about you?
: The notation is called Knuth's up-arrow notation. 3^3 is 3 times 3 times 3. 3^^3 is 3^(3^3). 3^^^3 is 3^^(3^^3). 3^^^3 is used as an arbitrarily large quantity so that there's no situation where it's "too small".