It probably won't hurt them. I incubated mine in the tank with the adults because I had just gotten rid of my incubator setup thinking I wouldn't get any eggs after a year and a half with no signs of breeding. There was a lot of fluctuation before I got them put in the right spot and those have hatched already. The only eggs I've lost have been infertile since my girls are 7 or 8 now.
So it's highly unlikely that a few hours will hurt them at all.