Every padlock comes with two keys. Make two sets of keys, and hang them in separate key release mechanisms on the ceiling. Always use both sets of keys! The ice key release mechanism is incredibly reliable, the keys are simply guaranteed to come down, but still other things can go wrong. For this reason, you must always use two sets of keys.
One thing that might go wrong is that the keys fall out your reach. Check in advance that the keys will fall near your hands, and that they fall on the blanket on which you lie. If you connect a sock to the keys, as shown in the part on release mechanisms, the keys will not jump away when they fall on the ground, even when they fall on a hard floor. There is no need to worry about this.
The worst that can happen is that you break a key in a lock that does not belong to it. In that case, you will not be able to open the lock in which the key sticks, and you will not be able to open the lock to which the key belongs. Wait for the second set of keys, and you will still be able to open the other lock.
The risk of problems is much smaller if you know in advance which key belongs to which lock. Keep the keys in a fixed order, and always use the same lock on the same place. Mark the locks and the keys with marker pens.
Padlocks are very reliable, and I never had problems opening one, but one never knows. If a lock appears to get old, and difficult to open, then replace it. Both the hands and the ankles can be freed by opening one from two locks. There is only one lock in the crotch eight, but it is possible to get free without opening it, although it is a bit more difficult.
If you have connected yourself to something fixed, then make sure that there are two locks (or a lock and a screwlink) in this chain as well, and that opening one of them is sufficient to get free.