@dearjohnlock managed to get ahold of a better quality version of the script pic from Charles Street filming. I still can’t make out anything on the bottom part, which I believe is what Ben and the actress are filming, but I can make out a bit of the top. Above is the pic dearjohnlock posted, an enlarged and sharpened version if you want to try your own hand at deciphering it, and what I was able to get out of it. What I’m pretty certain about is in red, and what I’m less certain about is in blue. Please feel free to add to this or to refute any of the things I suggested.
My best guess is that this may be Smith talking to Sherlock in hospital (and calling him by his first name–I can’t imagine that going over well), which may go along with the theory that the scene with the window and the sign on Charles Street is part of something Sherlock is either deducing in his mind palace or hallucinating from his hospital room (see here and here for that speculation).