He realized, in the end, he wouldn't be able to dodge anymore. Does he have to make a false testimony? He couldn't possibly say it was Mai who stabbed him.
"Aaron... Why do I feel that you are making excuses about this." Sean grew suspicious.
"No... No, well... I really--" Aaron said haltingly.
"Then just do it and don't make excuses or I'll think you're covering up something... Or protecting someone like your sister thinks," Sean snarled.