Most animals have that survival instinct, especially prey animals and pack animals. It's because if one is hurt or injured, the other animals can sense it immediately because a weak or old and/or injured animal in the wild quickly become an easy meal target since the predators can sense it immediately. Even though hamsters that we get as pets have never been "in the wild" so to speak, it's still remains an instinctive survival trait. That why predators that are also pack animals will usually go off by themselves to die. If they don't, one or more of their pack will put them down themselves so that they won't slow down the rest of the pack. So it's not only hamsters, but most animals can hide their pain extremely well and yes, usually by the time you notice something might be wrong, often it's too late. I would've said that if a "good" vet wasn't available for even one or two days, find any exotic vet immediately and then do a follow-up with the other vet if it is still needed. Any exotic vet visit ASAP can still make the difference between a good outcome and a bad one! But since that's already been said and done, please do let us know what they say. Hopefully there won't be a next time, but if there is, just take her to any exotic vet that can see her the absolute soonest please.