First time happening

a bit delayed from initial post but... went for a "test drive" last week after DH made a few adjustments to steering. All seemed fine as we drove down our hill (~1 mi of narrow curving road)and turned left on the main road. As we made a right turn at the intersection heard a loud noise. As DH pulled to side of road about half a block from intersection he said basement door on driver's side opened (could see it in the mirrors) - I said sounded like more as I headed out the door. There was our joey bed - the one that goes all the way through - in the middle of the road/intersection. As I started running for the intersection saw fellow in pick-up pull over and drag it to the sidewalk. He jumped back in his truck and waved as he drove off. Thank goodness for the kindness of strangers. And thank goodness this happened at low speeds and nothing and nobody was damaged/hurt. Still not quite sure what happened or how the latch mechanism on the tray slide got past all the catches/stops/blocks. No matter, we have now added positive blocking to all slide out basement trays to be used when traveling!