The math is easy to figure out to see how many newtons are applied on impact.
It’s like 1200N
Neck vertebrae can fracture at 1000N.
Death can occur at 1500N.
If the water bottle was more than half full, it will apply more Newtons.
If it was thrown more than 100 ft (which appears to be the case), it will apply more Newtons.
TBH, the culprit is lucky she wasn’t permanently disabled or killed.