While I would not bring it up, if specifically asked I would attempt to explain this in a positive light. It would be a HUGE mistake to give excuses, particularly excuses such as I had way too many things going on that semester. After all professional school is at least two or three years of I had way too many things going on that semester. So your goal should be to explain how this experience taught you time management and study skills which you applied successfully in the future. And how because of this experience you are a better more productive student who will be a wonderful asset to their program.