@purple if we're talking about vacuum decay, it's kind of irrelevant. the moment a higgs boson crests the energy hill and reaches a new, lower energy configuration, the laws of physics there have changed. all of the fields begin to adapt and transform in ways we cannot predict, and this change propagates out at the speed of causality, in a manner analogous to the universe's first big phase change when the weak force became decoupled from the electromagnetic force. there is literally no way we could see this coming, or tell if it has already happened and if the decay is headed for us already.