Complex sentence: But he was unable to control himself amidst the chaos, and ended up shooting a CO as well as injuring Chris Keller as the latter screamed in pain, Tarrant snapped out, and realized what he had done.
Split into simpler sentences: But he was unable to control himself amidst the chaos, and ended up shooting a CO as well as injuring Chris Keller. As the latter screamed in pain, Tarrant snapped out of it, and realized what he had done.