Fringe is inconsistent to say the least, and last night's episode was a good example of that. Now I know most people have been very positive about the episode, some even declaring it to be the best episode of the series. The episode had potential to be great, working off a premise that was sure to bring intrigue, but the episode didn't reach the next level.
I may be the only one, but I thought the plot was fairly predictable. Once I saw Walter enter the mental hospital, I knew he would be involved in some way, and was proven right once they revealed that Walter's brain tissue had made the people go crazy.
The final scene where we see William Bell was the one who took the memory to the other universe reinforced the ambiguity of who William Bell is and whether he is a force for good or evil. The twist was fairly big, but in the Abrams scheme of things, it seems like an insignificant drop in a pond too large and complex to understand.
There had been a push this season for the characters to become more involved in the Fringe division. We see Peter now fully engaged with the additional stimulus of everything he's learned about Walter. Walter is now more aware of his situation and limitations. Olivia was actually contemplating sacrificing Walter in the hope of cracking the Pattern wide open which would seem out of character, but considering what she's been through, we really don't know how far she or any of these characters would go. I am still waiting for Astrid to do something, and I would hope that the writers would give Jasika Nicole a more substantial role other than playing off Walter's eccentricity. I'm also wondering where Agent Jessup is. It seemed like she would replace Charlie or at least make progress with her Biblical connections, but we haven't seen her for I don't know how long.