I don't think there is any way Dos Anjos' injury was caused by fear, but the overtraining does make some sense. Also, I think I heard in an interview (MMA Hour?) he did not negotiate extra money for this fight which would be a horrible mistake. Perhaps he regretted this after thinking about how much Mendes made as a replacement and Aldo made as a champion and decided to look for a way out of the fight in hopes of taking advantage of a once in a lifetime payday.