Step out of his squad after being assaulted with his gun nearly taken away and one or more unintentional discharges occurred as a result of that assault?
By the way, BOTH of the perps attacked him in his vehicle.
He never "pursued" anyone. He staggered out of his vehicle after having suffered a serious head injury inflicted by TWO attackers. What was he supposed to do? Sit in his squad until they came at him again?
Drive away?
Reason I said hero complex is the idea that he had to deal with them both alone.
And two attackers? I saw a photo that supposedly represented a bracelet Darian previously had around his wrist but maybe, if it is the bracelet, maybe it fell off while fighting, maybe it fell off while getting the heck out of Dodge...