dissociation for me has always been much as you describe a good thing an escape. when it happens not it is much more like being drawn into the void and I have to fight to remain present. not long ago I had a really emotional day at T and then went to my survivors group and when I left I did as you describe. no ticket,no destination just gone and I WAS DRIVING! went 45 minutes or so in a random direction and when I got back I had NO IDEA where I was very freaky. so yea man you are not alone. it is a hard thing to control basically now I keep a gps in the car and set it so as it "speaks" it keeps me present. I think those things are the best we can do man.
hope it gets better
Towards thee I roll, thou all-destroying but unconquering whale; to the last I grapple with thee; from hell's heart I stab at thee; for hate's sake I spit my last breath at thee. let me then tow to pieces, while still chasing thee, thou damned whale! Thus, I give up the spear!"