[nosmatarmut]

In that scenario, it wouldn't make a difference what you choose.

If you were so inclined to take Box B's million, Omega would never have put that million in the first place.

The only way for Omega to put that million there is if you weren't inclined to take Box B - despite the million being completely visible to you - in which case you lose anyway.

The situation where Omega gives you the million, and you take it, just never comes up. Can't fool it.