Idk if killua is just worry cause he is her first friend or he didn't want hisoka to do that to gon cause he whant to be the one to take gons virginity and i Don't like the way hisoka stares at gon like he was about to rape gon it's very dangerous to gon to be in the same class room cause hisoka might have rape him and his to innocent to be experience that thank killua is there