Picking up Dignan's post from the other thread, but this time without spoilers...

On Mohinder:
Clearly, it would have been more rational for Mohinder to call "The Company", but then it's also reasonable to say that he was totally freaked out and didn't know what to do. If you wanted to get more technical, what are the odds that a phone connection with two wireless handsets was good enough to be able to pick up the sound of a cell phone generating touch tones? All the super-hearing in the world wouldn't help you hear a signal that wasn't there in the first place.

What really matters is that Sylar had his moment of ethical confusion, Mohinder was no help, so he reached out to (and killed) his mom, which in turn solidified his bad-guy credentials and made him think about being the President. That whole thing seemed a bit forced to me. They're trying to humanize him now? Why not earlier?