"So it was a trap..." Painter's expressions darkened, as realization started setting in.
"It was a deal. We both got what we wanted," Elias replied, knowing that the promise was the only thing holding that man back from killing him.
As for how long that promise was going to be effective, he couldn't be absolutely certain. That's why he didn't completely rely on that promise. Getting that promise was simply the first step of his plan.
"Also, he didn't tell me anything. He just made everyone believe that he told me something, so he could have some entertainment."
If he told the truth to the Painter when he was getting killed, there was no way the painter was going to believe him. But now that his life was more or less secured, he didn't have much of a reason to lie. It was at this point that his words held more value than before.