Maybe Rock's ability to see traps also allows him to see whether or not things are cursed. As for Mephisto, he's really enjoying himself watching the show and because Mephisto got hungry, he even got some popcorn to eat.
And we can say that Iruma, by preventing Rock from stealing various objects and some of those objects or even all of those objects are cursed, Iruma manages to easily rehabilitate Rock and Iruma prevents Rock from being cursed, in other words, Iruma kind of saves Rock's life.
And as a side note, if Iruma could rehabilitate a thief who's been around for over 300 years, I think it might be easier for Iruma to rehabilitate a terrorist like Kiriwo, for example.
Although I think Shakky is more or less frustrated that Rock doesn't steal any cursed objects, so she can capture Rock later. But let's look at the bright side, I think Shakky might be thanking Iruma for rehabilitating Rock.