I had the same thing happen three summers ago. Not very good, trying to do something dumb... one foot came out, the board flipped up and carved a nice digger out of my knee. The worst part was a twisted ankle (that still hurts) from the board rotation. I kept thinking "Dude, you suck, you're trying to get better and this happens??" A lot had to do with lousy bindings.
Regardless, Now I strap those things on to the point of going numb after a set. Yeah, I still suck but my feet aren't going anywhere.