I think this is an important topic. Quantum immortality is Very Bad if it turns out playing quantum Russian roulette is the right thing to do.

Although in fairness, you probably shouldn't expect to be in agony forever. After a certain point in time, you should expect most of your surviving, conscious branches to have lost as much brain function as possible while still remaining alive and conscious. I assume that means you'd lose inessential things like sensory perception or sanity.