Oh I bloody hate it when that happens. I've never done anything as cool or important as panel speaking but everytime I've ever had some type of appointment, that's when entire zipcodes decide to hit the highway all at once. I hope the rest of your day at con was good though!
This is why people put lifts in their trucks. Get a big enough lift and some tires, and suddenly, that caravan of minivans ahead of you look more like speed bumps in an elementary school parking lot. haha