Leareth finishes his water, which is maybe a questionable plan; he spends a while holding still and taking deep breaths until he feels less like throwing up, and then picks his way through about half of the food while he tries to think.
First priority, piece together an actual model of this world so he can– no, stop. Before that.
Priority one: sort out his internal priors around the question of 'still in Angband, yes/no', and then he can decide whether it's even worth trying to have beliefs about reality.
This is inconveniently hard to reason about, because his instincts have some very strong, and conflicting, opinions on it. Five years' worth of "not even worth trying to assess, assume still in Angband" and a more-recent but less-total-time year of redirects toward the various arguments against, which are more or less convincing at various times but he tends to fall back on the thing where no one is asking him to do things and that lowers the stakes. Or he stops trying to do reasoning about it and just obtains hugs until his brain stops screaming.
Not an option, now, but he does have paper. He can do this. Just think about one thing at a time, and write it down, and then it's there...
Leareth spends a long time methodically going through the past year in his head - and skimming over a lot more of the years-before than he would really prefer, but he has five years worth of memories and they're even mostly in order now and it does seem important data to check whether this whole situation is...at all on-theme...for any of the Melkor rescue hallucinations.
It's not, really? Melkor doesn't lack creativity but it generally wasn't pointed at 'detailed and very very weird alternate magic systems'. There are a couple of fake-rescue-memories that involved ending up in some third other world, but via accidents with more recognizable-to-Leareth magic than "being eaten by a fucking snake", and they have less random peripheral detail. And - there are rescue memories where supposedly years had passed, but Leareth also remembers going over those with Melody and noting that the 'years of subjective time' were mostly backfilled-and-inserted memories, which might pass muster at a quick glance but aren't convincing otherwise.
In particular, at least according to the supposedly-recovered memories and subsequent processing, Leareth has a cached conclusion that Melkor...never really figured out how to interface with Leareth's internal mnemonic system? Sometimes there would be backfilled record-keeping, but that, too, was never quite convincing.