I showed what was happening to the generator repairman. Even though he had been told what I had seen he still startled and jumped when the dipstick blew past him. I had to chuckle a bit.
I took a couple of videos showing the dipstick getting blown out. One video that I took only shows a loud "pffft" sound and a puff of mist because the dipstick was in tight to begin with. I lightly pushed in the dipstick so it wasn't in all the way and took the following video where you can see the dipstick more gently pop out.