A few minutes ago, Katherine was carefully watching all of the students having their own unique matches; she initially thought that something bad had happened since Bella called for her, but when she saw that Riley's opponent was struggling against him, she just shook it off.
If it was before, then maybe Katherine would be extremely worried; but she knew how abnormal Riley's control was with his telekinetic abilities-- nothing was going to happen unless he willed it so.
And so, she just gave Bella the thumbs up and continued to watch the other matches. Her eyes, thoroughly looking at potential trouble… but everyone was careful, even with the lessened restrictions regarding harming your opponent.
It would seem the training that they have been doing all these months was working. But Katherine was sure that most of the merit should be given to the tragedies and events that they have experienced first-hand.