Complex sentence: The injuries of the survivors ranged from light to critical, and were inflicted either from gunshot injuries and/or during fleeing accidents and their ages ranged from the late teens to their 60s.
Split into simpler sentences: The injuries of the survivors ranged from light to critical, and were inflicted either from gunshot injuries and/or during accidents while fleeing. The victims' ages ranged from the late teens to their 60s.