They taunted him 'unmercifully'.
an 'unmerciful' attack
(..) when he's riding his horse. To my wife- That is not your business. And now they love Maximus for his mercy. So I can't just kill him, or it makes me even more unmerciful! The whole thing's like some crazed nightmare. He is defying you. His every victory is an act of defiance. The mob sees this, (..)2000 Gladiator