From what I read, the problem is that if one engine is lost, then for up to five hours, you can expect the cabin to cool down to below freezing temperatures. This is because in the worst case power is not available to heat the cabin and/or pressurize the cabin, and so pilot takes the plane to a lower altitude that has barely survivable temperatures such as one finds at the north pole.

So bring a parka even if your destination is a beach.