Another school puts the panic snap near the wall since a horse in a panic is not easy to get close to. Wherever you put panic snaps, test them periodically. A single piece of baling twine can also be used as a breakaway spot in cross-ties. This can be cut with a knife it if doesn't break first. A horse can flip over in cross-ties that do not break.
Ball continues on the subject of tying.
People love rubber bungie cords, but if they stretch before breaking, the snap can fly back with such force it can pop an eyeball. I like to tie a piece of breakable twine on both the horse end and the wall end and not use anything that will be elastic. If you tie with quick-release knots, make sure they do release, even after a horse has pulled the rope tight. Doors need to be wide enough for a horse to pass through safely. Latches should slide flush with the doorframe.