Severus remained calm on his exterior, though there was quite a lot of shouting going on his head. Much of it was directed at Lucius and stupid idea of pushing his son at Potter. And he would have very much liked to have pointed out that Potter woke up in HIS bed, not Draco's!
Instead, he said quite calmly, "I think it would be a disaster and Draco will only end up hurt by it."