S01E15: Life Support

When the gun belonging to a critically wounded police officer drops out of his holster in the E.R., the distraught brother of a man waiting for a donor heart picks up the weapon and threatens the staff unless his brother receives an immediate transplant; as Aaron and Danny operate on the wounded officer, one of the exploding bullets with which he was shot goes off and severs two of Danny's fingers; Geri performs a successful reattachment, but Danny may be facing the end of his career as a surgeon.