that's basically what I think is the point
SPOILER ALERT
that he came to the conclusion that was insane, realized it, but realized he didn't want to continue living in that world, so he fakes being insane in the last scene so they'll lobotimize him hence his closing lines
I hated the end of that movie. What really would have sold it for me would have been a bit more ambiguity. I would have loved one line (and one line is all it would have taken) that perhaps insinuated that Teddy actually was sane all along, and the establishment convinced him that he was insane. In my opinion that would have made a much better film.
oh wow it's a series? never even heard of it