A centipede with its legs like that is usually dying, but death isn't as clear cut in centipedes as it is in humans, so you may still see it moving (and it may also be capable of biting) even though it is past help.
It doesn't have any obvious signs of mycosis, which is what usually kills pedes in captivity, so it doesn't look like its your setup that caused it (unless temp is way off - what's it at btw?). If you say it was "fine" earlier in the day (by which I assume you mean it was definitely not sluggish) then it's not old age, or a disease as those tend to be slow acting. It could be something it ate, or ingested, an injury, or something toxic that got in.
If you want to save it, put it in a small container with dry substrate and nice high temps (25-28) and a clear water dish.
In fact, it looks like it's either dehydrated or hasn't fed in a while. You can pop its head in a water dish see if it drinks (it won't drown as there are no breathing holes on its head).
Other basic questions: Does it have a water dish, is it de-chlorinated water, has it been eating, could it have come into contact with a toxin, did you change its setup recently, etc... ?