Alita's slave told her that he was thirsty. Alita - being a merciful mistress - grabs a bottle of water and wants to give it to her slave. But then she hesitates and thinks about giving her slave a little punishment while doing him something good. So she opens the bottle and spits into it - but her slave refuses to drink the specially flavored water so she forces him to drink it and spits directly into his mouth afterwards. Maybe next time she'll not be that merciful.