I debated whether or not to put something down, but in the end, decided that I really didn't have to or want to add anything else. Everything that I could already sum up in 500 words or less has already been plastered all over my application.
also, take note about their LOR requirements. if you DO NOT have a prehealth committee, you have to send in 4 letters from different departments (all from different). or so that is what everything says. i emailed asking about this requirement and they said that if you can't do the 4 letters that you need to explain why in that little box and list who they should be expecting them from.