If Ace wanted, he could've escaped before and there was a huge chance that Henrik would not chase after him because of his duty as an evaluator. He might even think the other party had escaped after they were found out since he won't be able to sense Ace's cultivation, so he won't take such a risk to confront an unknown enemy.
But Ace didn't escape and decided to confront Henrik like Pablo, so he could get close to him. He knew this was his only chance if he wanted to succeed in the system's mission without being caught.
That's why he acted like a coward, so he could make Henrik drop his guard and Henrik just played in his hand when Henrik saw he was just an insignificant iron demon and his cultivation was akin to an ant.
Now, all he had to do was to make sure Henrik would let him go, and he got the chance to pickpocket his storage ring. All he had to do was to escape afterward, but he can't be too obvious about it.
