That might have gone a lot more poorly for Keltham if he didn't have an Enchantment Foil and a Protection.  (From Good, as it happens, but it still counts!)

Keltham now knows that somebody tried to use mind control on him.  He could very easily pretend to play along with it if he wants, let it look exactly like the enchantment is controlling him, but that doesn't actually seem smart because the compulsion is telling him to freeze in place.

That might have gone a lot more poorly for Keltham if he didn't happen to have an Enchantment Foil.

Keltham now knows that somebody tried to use mind control on him.  He could very easily pretend to play along with it if he wants, let it look exactly like the enchantment is controlling him, but that doesn't actually seem smart because the compulsion is telling him to freeze in place.