Well, if Sylar found a way to kill Radiation Man that didnt cause him to explode .. maybe. Of course, with one villain knocking off another (Radiation Man is continuing his journey over the edge, putting him more toward the villain character than victim at the moment) that eliminates another fight sequence .. if Peter only has to stop Sylar and not Radiation Man .. well, then they'll have to find a whole new plot for season 2 <g>
What's interesting is that Peter also hasnt seen Radiation Man in his dreams, his dreams all focus on how to control his own power to stop the 'bomb', none of them tell him to avoid Radiation Man. (So, potentially it
could be Sylar, no reason for it not to be for the continuity) He only sees the other supers racing away, Mohinder smiling, then racing away, Matt the traffic cop urging everyone away, Claire/cheerleader runs to him, apologizes and runs away (which reminds me of the rules of Pangerian Pangalactic Hockey, but never mind) and then only Simone and Nathan advance toward him. Isaac always takes Simone away, and Nathan looms rather menacingly, despite the dialogue being friendly.
Peter says he cant control 'his' power, Nathan refuses to leave.
Sometimes we see Claude Raines The Invisible Man (I cant believe they are actually calling him that .. I could see Chris was joking when he said it, but HRG seemed quite serious!) laughing or committing the crimes Peter saw him commit already ..
I think we need a new dream sequence with more clues now,

this one's been used up!
But we never see Radiation Man or Sylar. (Or even HRG or Blink) Maybe because none of them represent the solution, and his dreams only give him the pieces he needs to make things work, and leaves out all the other dangers involved. So if HRG gets hold of Peter, he's going to make things worse. (Well, duh, after he programmed Isaac to kill him.)
I wonder if Isaac lets himself be killed? When Hiro found his body in ep 2 there was a huge painting of a gun going off with the bullets flying straight up - I always thought it was Sylar stopping the bullets before he killed Isaac, but maybe its about Isaac and Peter. Maybe Isaac is willing to let Sylar kill him after what he did.
I know Hiro wasnt allowed to save Charlie, but I wonder if Peter could just run time backwards and save Simone by lifting the bullets out of the air before they hit her - Hiro was able to send that bullet backwards in time, but nothing else. (I'm reaching, I realize, but I still want to find some loophole to save Simone. Even if it isnt possible.) If that works, then Isaac will leave Peter alone and just try and keep Simone temporarily away from him, as in drive her out of town, even if just till after the 8th. Peter might go along with that, if they can save her.
The fight between Peter and Sylar could be awesome - we have the hearing ability, Peter has invisibilty, plus, if he gets close to Sylar he'll have the hearing ability but probably no way to control it - both have the 'Big Voice' ability, and can hurl objects across a room with speed and accuracy enough to make Vader jealous. Peter has the abilities Sylar craves, the healing, the flight (tho Sylar's leviation makes it hardly necessary) and Peter may even pull Eden's abiltiy out of a hat. Sylar, tho, has been working with controlling multiple ablities longer and can absorb and use them faster than Peter does.
It may take more than one round or two for one of them to finish the other off...