Perhaps he believed his reasons were straightforward. I do believe the evidence points to Bigby's account being true, however.

[ and she was. there when they woke up in the crime scene so???? ]

I do not know that speculating about people's motives is exactly helpful. We still have no idea why Luke was doing any of this, or if he was doing it of his own free will, for example. I think the idea that we ought to assume the Staff are out to get us simply for their own pleasure is perhaps a little naive...there are undoubtedly deeper levels to this game than any of us know, even them. It makes the question of "why" a rather stupid one.