The moment they realise Zero = Black Phantom, even 10X the rewards, player wouldn't want to complete this quest.
At worst, he can send a quest on his own to counter that one, that could be fun too.
I can sense it, the time is coming where the players will learn / put the connection between who Han Xiao, Zero and Black Phantom is and Han Xiao can finally do away with that damn Mask!
Did HX get that mission too? Or at least know about it? If so, he could put up a mission for those who see him to help Zero escape, with a bigger EXP reward and some skills and/or equipment or something.
Can already see Aurora, Hila and HX being all lovey dovey.
How will Bennett and the 6 Nations react when they learn that Zero killed the Germinal Boss and Zero = Black Phantom.