<P> Reed ultimately realizes that the mistake was committed by April , who forgot to check the patient 's airways , already swelled by the smoke , after being distracted by a patient with an axe stuck in his chest . Richard then fires her . The residents are shown having various reactions , as some complain about the absurdity of April 's mistake , while Cristina shows empathy for her former enemy . Derek then criticizes Richard , telling him he was initially responsible for the situation by setting chaos in the ER with the merger . </P>
<P> Reed ultimately realizes that the mistake was committed by April , who forgot to check the patient 's airways , already swelled by the smoke , after being distracted by a patient with an axe stuck in his chest . Richard then fires her . The residents are shown having various reactions , as some complain about the absurdity of April 's mistake , while Cristina shows empathy for her former enemy . Derek then criticizes Richard , telling him he was initially responsible for the situation by setting chaos in the ER with the merger . </P>
who killed the burn victim in grey 's anatomy
who killed the burn victim in grey 's anatomy
April
April