...That is new and different - well, maybe, maybe not, he knows Melkor has been messing with his memories, that's why it isn't safe to take actions or have goals or reason about the world. But he doesn't remember anything like this, and it's not any kind of Velgarth magic.

He can float for a while, repeatedly not having preferences about what's going to happen, but he is gradually getting more panicky about the situation. 

...the anxiety is getting worse over time? I'm not sure why, do you have a guess?

:Hmm. Your subtle arts might be alarming, since they are not something this version of me would know of, but in that case I would expect it to be more of a sudden spike when you started. Though, it is difficult to model myself under such different circumstances so I am not sure my predictions here are reliable: 

He thinks for a moment. :I could come read him again but that is likely to make him more anxious. You have my permission to look at more things if it might help figure it out, since you are doing things anyway: 

If you say so.

"You're getting more anxious. I have the other Leareth's permission to use my ability to find out why to see if I can help; you can contradict him if you want, but I don't expect you to believe me, I'm just letting you know."

Peek.

In which case she'll observe Leareth going through several cycles of noticing that something happening near him is surprising-or-confusing (in this case, her talking to him), on one level being alarmed about this, while on another level repeatedly stepping on any attempt to interpret said confusion, or care one way or another whether the surroundings are alarming. This is a fine moment, he's not being tortured right now, which doesn't offer any prediction about the next moment but making predictions isn't safe. Not safe to reason, not safe to have preferences or goals, definitely not safe to take actions but he's trying to cut it off as early in the stack as possible. There's quite a lot of cognitive effort going into that, actually. 

Still, on an instinctive level Leareth can't help being scared that things are happening nearby, things which don't make sense, and probably at some point one of them is going to be bad. 

"I can knock you unconscious again," she suggests.

He is very firmly trying not to have preferences about that, in addition to not answering her. 

Yeah that's par for the course. She updates his counterpart.

:Noted. Go ahead and knock him unconscious, if it will not make the rest harder, that seems like a clear improvement: 

Then Angband Leareth will wake up a couple of hours later alone with all his memories back.

There are a lot of them! They're not exactly out of order but they're very choppy, with sudden switches and transitions. Also most of them are really horrible.

He tries not to do anything or have thoughts. 

Someone brings food and he is now very obviously compulsioned to eat it. He tries not to have any preferences about that either, or notice any confusion about how Melkor can imitate compulsions; he's not completely succeeding at the latter. 

The other Leareth goes in after he's eaten and spent a while lying and staring at nothing. 

:I am going to look at some of the memories: he sends, and starts doing so. 

...gods why are so many of them torture, he really doesn't want to make the other Leareth dwell on those and he doesn't find them very appealing to look at himself either; they're not really information-containing.

It's less that he's scared, exactly, and more that everything is very loud and overwhelming and he keeps having his mind yanked around by the probably-fake-other-Leareth, for inexplicable mysterious reasons, and he's trying not to have any preferences about the situation but it's really hard not to want it to stop. 

Ugh. 

He backs off. :Bella? I am trying to find the memories of him doing magic, and having trouble getting to that instead of awful torture memories. He is understandably quite stressed by this. Is it something your arts are better at?: 

Uh, if he helps it's easy, if he doesn't help I might or might not be better at it? If I can find a couple of memories of him doing magic I can find the rest, so maybe you could prompt me with some that would match and then I can find more recent ones.

:He is not helping. I did not actually explain what I am looking for or why, though, it seems that explaining more things is mostly going to be bad. I can find a memory that both of us should have, sure: 

He'll have to dig around for something salient enough that he would definitely recall it decades later; permanent Gate installation in the facility where he first recruited Nayoki, that'll do. 

With some rummaging she can find the corresponding memories in Angband Leareth and do her own signposting of magic memories, slightly laboriously, and then try to find recent ones.

How recent? There are lots in Arda, before his capture; after that it's much harder to find anything.

The memories of Gating are there. It doesn't seem like there's anything else. 

I found the Gates, I think that's it.

Leareth checks himself as well. :I see. Thank you: 

:I am stopping now: he tells the other Leareth, and backs out of his mind. He gets up and leaves the room. 

:Now maybe we can leave him alone and let things be very boring for a week?: he sends to Bella. :That was the most time sensitive piece: 

I think so, yeah. I'll call Other Vanyel back tomorrow and let him know.

:Thank you: 

Leareth checks in with the Healers, makes sure someone is on duty to keep an eye on Angband Leareth from a distance, reminds them about making sure he eats and drinks at reasonable intervals (they don't really need reminding of this, they're Healers, but it's possible he's fussing because he can't think of anything actually useful to do.) 

He lies and drifts and eats when forced to do so. 

Bella scrolls her interplanar transit and stares at it till there's a copy in her Valinor for Rúmil and Fëanáro to look over. They all start poring over it for errors and places to add contingencies to make failures less catastrophic.

The next day she calls Vanyel and tells him they found only the memories of the four expected Gates and not any other magic performed since then.

He's talked with Fëanáro and Maitimo extensively in the meantime, and they are very suspicious. 

:Thank you. Do you know how Melkor got him to do the Gates, er, and why he stopped?: