For something to experience pain, some information needs to exist (e.g. in the mind of the sufferer, informing them that they are experiencing pain). There are known information limits, e.g. https://en.wikipedia.org/wiki/Bekenstein_bound or https://en.wikipedia.org/wiki/Landauer%27s_principle
These limits are related to entropy, space, energy, etc., so if you further assume the universe is finite (or perhaps equivalently, that the malicious agent can only access a finite portion of the universe due to e.g. speed-of-light limits), then there is an upon bound of information possible, which implies an upper bound of pain possible.
Yeah, which I interpret to mean you'd "lose" (where getting $10 is losing and getting $200 is winning). Hence this is not a good strategy to adopt.
99% of the time for me, or for other people?
99% for you (see https://wiki.lesswrong.com/wiki/Least_convenient_possible_world )
More importantly, when the fiction diverges by that much from the actual universe, it takes a LOT more work to show that any lessons are valid or useful in the real universe.
I believe the goal of these thought experiments is not to figure out whether you should, in practice, sit in the waiting room or not (honestly, nobody cares what some rando on the internet would do in some rando waiting room).
Instead, the goal is to provide unit tests for different proposed decision theories as part of research on developing self modifying super intelligent AI.
why do I believe that it's accuracy for other people (probably mostly psych students) applies to my actions?
Because historically, in this fictional world we're imagining, when psychologists have said that a device's accuracy was X%, it turned out to be within 1% of X%, 99% of the time.
This seems like an odd choice for your primary example.
Is it perhaps worth writing a (short?) top level post with an worked out example of the refactoring you have in mind, and why matrix multiplication would be better than nested for loops?