Joseph tells Suresh that Samuel doesn’t know the extent of his power. He does make it clear that the increasing of powers is, in fact, specific to Samuel. That was not explained earlier, but I now regret my criticism. Joseph tells Suresh to burn the film and go back to India – Samuel can never know what he’s capable of. We then see Samuel sneaking around the trailer, listening in.
Heroes 4-9 “Brother’s Keeper”