No Escape
Honestly, horse stalls were death traps for anyone without good traction. Ned knew this fact; it was demonstrated over and over on rainy days when he or the horses slid over the gridlike flooring. Obviously there were worse places to be. A walk-in freezer, for example. A safe or meat locker would be a horrible place to be. Sitting in a dark, locked room with who knows what hanging around seemed like a nightmare. It would be even worse with temperature regulations, he could freeze or burn to death slowly. It was a horrible thought. Though there were obvious components that would prevent such accidents, it could actually be purposeful. There would be a door, but with no means of breaking out. There would be no escape.