That's the one where he pretends to be sick and goes all delirious, right? It's possible - it'd certainly be a twist in the plot - but I don't see how it'd apply here. I mean, there (if I remember correctly) he was basically acting helpless so that someone would spill the beans around him - here, on the other hand, he just went up to talk to the guy who he'd been hired to help; I fail to see how it would help the situation for him to pose as a murderer. (Of course, I'm not Sherlock Holmes, so I could be wrong, but...) No, I think that something happened so quickly that even his analytical mind was unable to keep up, a situation which he is NOT used to, and as a result, he's temporarily at a loss for words. (I'm reminded of the sequence in 'The Great Mouse Detective' where Rattigan outthinks Basil, who is deeply shamed and humiliated, and basically stays that way until events force him to get over himself. Since that was a Holmes pastiche, this may not be a coincidence.) My guess is that either A: in the solitude of the prison. he'll have time to pull himself together and work things out, or B: he'll have to enlist Watson's help, basically making him play the role of detective for once. Either way, it'll be interesting to watch.