I ran in a 5k kidney benefit today. And it was the same deal. You could choose to run or walk. I had signed up to run, but I hadn't been for a jog in about two weeks. Some of the cardiologists whom I work with were planning to go, and I just felt stressed out by the prospect of running in front of them.
The sort of sad thing is that what actually motivated me to go was the free t-shirt (a smiling cartoon kidney in a sneaker). I ended up finishing today at 28:33, and I was okay with that. I wasn't in the mood to totally bust my butt, but I think I'm getting better at pacing myself. It was definitely a couple minutes faster than the last 5k I ran (although that time I was pushing a stroller).
Next 5k? Maybe May (local free clinic benefit).