What's the correct ruling on this situation?

[Brettski]

I think one of the most important lessons here is that a hand is never mucked until it's actually in the muck. Rulings on this do vary from place to place, but a hand that a) hasn't been properly tabled and b) is irretrievably mucked can't risk being ruled "live" under almost any circumstance.

When I have conducted dealer training I have always emphasised the importance of mucking folded hands quickly and irretrievably. This eliminates many grey areas, and means that arguments such as this one simply don't arise. It also makes the floor's job much easier when they are called over to disputes such as this.