They fear being humiliated and losing face. Putin in particular.
So you don't want actually to humiliate them. The aim is to use their fear of it to change their behaviour. The more we invest in weaponry in Ukraine, the more it becomes apparent to Putin that Russia will lose catastrophically, the quicker his behaviour will change. He's already arresting those around him. That shows he's on the ladder of fear. So keep it going. He's telling us it's working.