He knew that night, and then the next morning he regressed:
"So what's our next move?"
"You tell me"
"Gotta get off this rock Chuck, get back to the mainland, whatever is happening here is bad".
*Doc shakes head.*
"Don't worry partner, they're not going to catch us"
"That's right, we're too smart for them"
"Yea, we are aren't we?"
Chuck is his fantasy sidekick Marshal if you recall.
We're debating the end of a movie, so I'm not getting crazy into this argument, btw.
But re-read what I wrote in my earlier post.
I know he began acting like his previous character. But he fully accepted what was about to happen. If he was entirely his other character, that of the marshal, what would have prompted him to just get up, and walk to the doc, security guy, and orderlies, never saying a word and merely walking away with them.
He did that because he
knew that acting the way he was acting (like the marshal) would land him in the lobotomy room.
Thus, subconsciously he was a changed individual, aware of all he had done, and making a move to end it once and for all.
The marshal was never once aware of what he had done, of the fact he was acting, or any of that.
I maintain he didn't "regress" entirely, but instead, was now only acting. He regressed consciously, as if acting out a part and trying to live it, to maintain harmony in his mind, but every other part of his mind was aware. He likely even felt he could no longer act out that role and feel like he had previously.
His character wouldn't have been taken without a fight if he had fully regressed.