Not necessarily. If I believed that my continued survival would cause the destruction of everything I valued, suicide would be a value-preserving option and analgesia would not be. More generally: if my values include anything beyond avoiding pain, analgesia isn't necessarily my best value-preserving option.
But, agreed, irreversibility of the sort we're discussing here is highly implausible. But we're discussing low-probability scenarios to begin with.
my continued survival would cause the destruction of everything I valued
This is a situation I hadn't thought of, and I agree that in this case, suicide would be preferable. But I hadn't got the impression that's what was being discussed - for one thing, if this were a real worry it would also argue against a two-thousand-year safety interval. I feel like the "Omega threatening to torture your loved ones to compel your suicide" scenario should be separated from the "I have no mouth and I must scream" scenario.
...More generally: if my v
via.
Sounds like sour grapes. I'd heard of people holding such sentiments; this is the first time I've actually seen them expressed myself.