Since we currently can't construct a collider with the kind of energy needed and it's a possible (not certain) outcome, I'll relax. . If our Universe really is a metastable (local minimum) vacuum, why haven't natural high-energy events like very energetic cosmic rays already caused a vacuum catastrophe? Maybe we've just been lucky so far. Well, if a lower energy bubble is out there, I hope it's billions of light years away.
If you want to geek out a bit more, good ole' Wikipedia has some more info here.
IMO,what good will it do to worry about it all. My concern is the next camp site and trip.
Break open the beverage of choice and take what ever comes our way.
We seem to have a consensus around here. I also am not worried in the least about it. We all gotta go sometime. In the meantime, I am doing stuff I like doing.