Did the bindings pull out the inserts or where they just loose? My bindings are starting to show a bit of wear so i make it a point to check them before i go ride. After about 3-4 days of hard riding my bindings start to loosen up a bit and will wiggle a bit. My hill has screwdrivers and stuff at the top and bottom of most lifts so when i notice it i just fix it.
I did had something sorta similar happen once on at the end of a park run. Right after i came over a roller my rear binding decided to rotate like 20 degrees but was still attached... Luckily it was only a short ride to the lift so i made it down but it was super awkward lol. Just be glad you weren't going any faster or you really could have got fucked.