Tony got Bruce to drop his arm with that heartfelt mini speech, at the very least. Which meant it was working. He had to admit he missed working. He missed the world, but he was still convinced that he should probably just kill himself and rid himself for the betterment of the world. Only Tony Stark would want him on his team.
Bruce sighed like it really hurt to consider it, but he was. "Tony, you know I can't," he said finally. "No one in their right mind would want to work with me in a lab after.." what happened, but he didn't need to finish that sentence, did he?