To be honest it was actually a piece of metal, that I think broke off the ankle of the pants, that got stuck in the boot. It's the first time anything like this has happened and I tried searching for the foreign object at the bottom of the mountain, couldn't find it, then started digging into me again. Normally I'd just wait 'til I got to the bottom again but there was a good wait on the lifts and I wanted to enjoy my ride down the rest of the mountain.
Yes, I was using rental gear, one of the reasons I'll be getting my own kit for next season.
The lacing system at the top of the Salomon F20 looks nice, I might try on a pair when I'm at the shop.