Arcs usually pull back anywhere between the .5 and .786 fib levels. I have seen some pull back only to the .382, but it is usually short lived before another fall occurs...not always though.
Arcs can be volatile to trade until they land, and even then can remain volatile for quite some time. They are volatile due to the extreme stance folks have but as a rule, a move this steep is not sustainable long term.
Human nature usually wins this battle, and folks sell due to greed or pure common sense. Short percent is low and NV is high. If you want to buy this pull back, just be safe.
If or when it falls, or lands, it usually does not happen overnight. There will most likely be "Pull Ups" along the way. Good luck!