Collapsed Honey Comb

I was shocked to see a full honey comb collapsed in the prime swarm TBH. So sad. Im not sure how it collapsed? The comb is attached on both walls, i cant see any singns of a mouse being in there. And the weather is cold so there is no way that heat could be the reason. Many bees are squashed by the comb, nectar flowing all over the floor ... such a waste ... now that they need the nectar most ...
I took out the collapsed comb and placed it on top of the out door feeding station so bees can clean it.