I am not completely indifferent to being tortured, so in your hypothetical, Kennaway, I will try to get Ming to let me go because in your hypothetical I know I cannot have a permanent effect on reality.

But when faced with a choice between having a positive permanent effect on reality and avoiding being tortured I'll always choose having the permanent effect if I can.

Almost everybody gives in under torture. Almost everyone will eventually tell an interrogator skilled in torture everything they know, e.g., the passphrase to the rebel mainframe. Since I have no reason to believe I am any different in that regard, there are limits to my ability to choose the way I said. But for most practical purposes, I can and will choose the way I said. In particular, I think I can calmly choose being tortured over losing my ability to have a permanent effect on reality: it is just that once the torture actually starts, I will probably lose my resolve.