In the end, the challenge was issued later than Alastair had expected it would be, but that it was issued mentally, with enough power to act as what Alastair assumed was meant to be bait, at least caught his interest. It meant Petrelli had taken the steps the attacks and threats, combined with Alastair's reputation, were meant to make him take. Embrace the power within, be vulnerable to corruption.
Leaving the pediatrician at one of his now many 'Hell' locations in search of a meatsuit closer to the location, he settled on a reasonable choice a block away from the site – a man with a wife, three kids, some sort of medical researcher. A person with not only connections, but a purpose. That usually helped when dealing with moral types and while Alastair doubted Petrelli's morals would last long in getting revenge for the torture of the older Claire and the threats against them all, it was still good to have more tools at his disposal like the soul in this shared body that he was currently controlling.
Armed with his own powers plus a great deal of information on this man and his family from pretty little Claire's head, Alastair moved toward where Petrelli was pulsing with power like a living beacon, ready for the first of what he was certain would be many specialized attacks.