Professor Stein has really stepped into the void (I really can't use the word 'breach' anymore) left by Harrison Wells' death (or rather, lack of ever being born). He's the new calm head of STAR Labs, the brains leading everything and figuring stuff out alongside Cisco. He's very enjoyable in the role, although it does mean that the other half of his character has been put on the back-burner. With Ronnie gone, he cannot become Firestorm anymore. Does that have some influence on what happens at the end of the episode? While explaining to Team Flash about the various breaches (dammit!) in the city, he appears to suffer from a heart-attack or something similar. Whatever it was, he isn't in a good way. We know he'll survive, as he's in Legends of Tomorrow, but what will the after-effects be?