Spoilers:
I was really hoping it would turn out the masked guy was Hiro's brother.
Seriously- they're having a moment, and he's suddenly like "oh you go on without me"
Where does he need to go? It's night time, and all his friends have been established to have gone to the cafe, where he sends Hiro to go without him.
The only reason he needed to go off on his own was so he could die in the fire. I figured for sure he was faking his death.