"Oh come on!" Do not give up that easily." Jin wanted to exploit the hammer's so called malice energy to get more benefits from the System. He knew that the hammer was able to do more but seeing that he was giving up this early might have reasons to it as well.
Jin was not dumb when he saw the malice energy turning into physical form and subsequently saw the hammer focusing all the energy towards Jin instead. It was a little bit of a shocker for Jin at the start but it was nothing he could not handle at the current state that he was in.
Yet at the same time, Jin could see that the Hammer was not giving its all, fearing that Jin was not able to handle the pressure and inadvertently caused an accidental explosion that would injure the rest. At the root of it all, the hammer was still kind.