Complex sentence: On one of his first days on the job, he overreacted when two inmates started arguing over an Uno game and pepper-sprayed them before accidentally spraying himself and Donaldson when Donaldson attempted to stop him.
Split into simpler sentences: On one of his first days on the job, he overreacted when two inmates started arguing over an Uno game and pepper-sprayed them. He ends up accidentally spraying himself and Donaldson when Donaldson attempted to stop him.