Fedor didn't lose. It was a doctor stoppage. The fight could have gone to the third round and then Fedor could have won the round or even found a way to win - he won the first round according to the judges' scores so if he won the third he would have won. Fedor only had a closed eye.
to be honest I thought I saw signs of Silva starting to gas at the end of the second, but then again there was no argument from the Fedors corner when they stopped it...
I've seen worse thumpings that were allowed to continue for another round, but I'm thinking the doctor saw something in Fedors behavior between rounds that had him stopping it...
with an eye like that it's up to the fighter to convince the ref to let it go another round.