#1 How did Claire lose Angela while holding her hand and walking down the hall? Did I just miss Angela and Sylar trading places?

#2 Were Sylar and Mohinder sharing research? How did Sylar know the relationship between Adrenaline and their abilities?

1) She let go of Angela's hand as she went around the corner, then when she reached back, it was Sylar's.

2) I don't remember him saying any lines about it, but a lot of people know what effect large amounts of adrenaline can have on the body. I think he was just intending to incapacitate her.

2.) Because he has looked at Specials' brains and he knows how they work.

He may have read a few things while stalking them. Maybe the adreneline was labeled "Danger, this will make them lose control".

2) He did read Mo's laptop..