Protect yourself at ALL times. Ortiz was frustrated, and committed a very nasty intentional headbutt to Floyd's face, which resulted in him getting a point, and his consciousness, taken away. Yes, Floyd took advantage of the situation because IT WAS LEGAL. It's not Floyd's fault that Ortiz was looking at the referee who was looking at the timekeeper.
The same situation happened in 2005 when Floyd fought Arturo Gatti. The two got tangled when Gatti ducked, and Floyd's forearm ended up behind his head. When Floyd pulled his forearm, he hit Gatti with two shots, which made Gatti look to the referee in protest. The ref did not get between the fighters, or say anything about it, so while Gatti dropped his hands and looked at the ref, Floyd dropped him with a left hook. The difference is, Gatti got up and then got thoroughly dominated over six rounds before his corner stopped the fight.
If those blows didn't end the fight, it'd b an entirely different story. People would be saying "Ortiz headbutted him, so Floyd got even" which would precede the inevitable victory for Mayweather, who looked superior in every way during the one-sided third round where he sliced Victor Ortiz at will.