One has to take into consideration that Heart and Pride are two different things.
What Margarito had going into and made him survive the fight is his pride, pride which he talked about a lot before the fight going into lengths saying he won't quit like Dela Hoya did. And with all he's been through, he came out to prove himself to restore that pride he lost.
Marg seemed to leave everything there in that fight without thinking of surviving to fight another day.
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