Even that was part of the plot forming in Mirage's processor. Every Decepticon that came to him for a rite got some form of a peaceful, calming rite, even if it was not the one requested. Oh, he hid it easily enough, under demands for courage and strength and, in one 'Con's place, luck in love, of all things.

He was never going to be able to view Brawl the same way again, really.

It wouldn't do much to delay what Megatron himself was planning, but hopefully, it would make his eventual escape all the easier.