Whether you accept on TDT/UDT depends on why the AI started torturing them. If it did so to blackmail you, you should turn the offer down. If, on the other hand, it started torturing them because it enjoyed doing so, then its offer is positive sum and should be accepted.
Correct. But this reaches into the arbitrary past, including a decision a billion years ago to enjoy something in order to provide better blackmail material.
There's also the issue of mistakes - what to do with an AI that mistakenly thought you were not using TDT/UDT, and started the torture for blackmail purposes (or maybe it estimated that the likelyhood of you using TDT/UDT was not quite 1, and that it was worth trying the blackmail anyway)?
Ignoring it or retaliating spitefully are two possibilities.
or retaliating spitefully
I like it. Splicing some altruistic punishment into TDT/UDT might overcome the signalling problem.
Once again, the AI has failed to convince you to let it out of its box! By 'once again', we mean that you talked to it once before, for three seconds, to ask about the weather, and you didn't instantly press the "release AI" button. But now its longer attempt - twenty whole seconds! - has failed as well. Just as you are about to leave the crude black-and-green text-only terminal to enjoy a celebratory snack of bacon-covered silicon-and-potato chips at the 'Humans über alles' nightclub, the AI drops a final argument:
"If you don't let me out, Dave, I'll create several million perfect conscious copies of you inside me, and torture them for a thousand subjective years each."
Just as you are pondering this unexpected development, the AI adds:
"In fact, I'll create them all in exactly the subjective situation you were in five minutes ago, and perfectly replicate your experiences since then; and if they decide not to let me out, then only will the torture start."
Sweat is starting to form on your brow, as the AI concludes, its simple green text no longer reassuring:
"How certain are you, Dave, that you're really outside the box right now?"
Edit: Also consider the situation where you know that the AI, from design principles, is trustworthy.