No, nothing he can't recover from. Putting them in a small, dark space (like a box) is usually best. Animals get less stressed if they can't see (counter-intuitive, I know, but true) so a in a little box they may even fall asleep. If not, they'll be unhappy but no worse for wear.
I've done countless 3-4 hour car rides with my gang and Daedalus could always manage to get out of his box, so after a few times of having to pull over on the high way to try to get him back in, I just decided he was OK riding on the headrest. He's docile enough that he gets up there and doesn't move or get freaked out. So this is how we go to shows or to the vet now if I'm alone in the car. Granted, it's unsafe for him, which is why I recommend a box first. The headrest is fabric so he has a good grip on it but if we ever have to stop dry, I don't know that he wouldn't end up as a blue pancake.