Hey there.
I'm not at PCOM but this is still relevant.
On some of my secondaries, there was a big blank space for whatever you feel like putting in there. Instead of rehashing my personal statement, I tried something different. I learned as much as possible about the school I wanted to go to, including projects that they were working on, what kind of academic successes they've had, etc. I used that knowledge to show them how interested I was in that particular school (ie kissing up a little). Well, it worked because my interviewer even commented that I seemed to be very well-informed.
Just a little psychological principle. If you already know that somebody likes you, then you are more likely to like them.
Use the opportunity to stand out!
Gluck