How is your humidity? How long have the others been pipped? If its only one that has been 10 hours you need to wait it out. If you open the bator all of the humidity could be sucked out and dry up the other eggs and then the ones that are pipped won't ever be able to get out. The membrane dries out and seals them in like shrink wrap. Having said that, alot of people will help them out, but you have so many that haven't hatched yet you could lose a significant amount of chicks if you throw off the humidity.
I had one that pipped and sat for a very long time. It didn't look like it would ever hatch and this went on over night. It was probably something like 16 hours or so. It eventually hatched, when I wasn't looking (the little bugger) and is fine today.
Then I had one that pipped and sat same thing, for a long time. He was my last egg to hatch and I was very concerned. I finally reached in and pulled off part of the shell for it to help itself out. It did get out, it was never robust like the others and didn't seem to know what to do in the brooder. It died the next day, I think from when they all huddled in the corner and this one wasn't strong enough to push itself out of the group.So helping them out is always a tough call. Some people say that if it can't get itself out of the egg on its own then it isn't meant to hatch and then others have helped hatch eggs and the chickens are fine to this day.
I would help if I know that something in the bator was off, humidity or temperature ,because then that is not something that is naturally wrong with the chicken and you could lose your whole hatch.
Thats why I asked about the humidity.
What kind of bator are you using?
I think if I were you I would wait for all of the others and not dwell on this one too much. It might surprise you.
Keep us posted .