I have a few experiences I can call up and almost get there in all of my senses, almost escape into fully, not like a PTSD Dissociation, but a guided re-entry into a happy and safe place I have been and remember well.
My best and easiest one? The split second of leaving shore in a small boat, like a canoe or a kayak or even a rubber raft, it's flight, it's leaving the restriction behind, it's a new realm that changes everything you were into what happens next. That moment is one I can pull up like a warp tunnel to come out of in a different place and a different time than where I was just a second ago.
Thats not a "safe place" but when fight/flight is getting close to taking over and I need to run, guess where I might be headed?