First of all, don't decide ahead of time who will try to find who in case one of you will get lost. The reality will dictate its rules. You need to be ready help each other.
Before this recital Vidas promised me if something will happens he will catch me. This promise had to make my life easier since the night before going to Nida, I broke the fifth finger of my right foot. So I had a hard time walking and sitting in the car for a 5 hour long drive. It may sound surprising, but during the actual performance in one spot Vidas got lost (because of the reasons you will read in the next paragraph). I even had to point at his score where he is supposed to play.
In addition, we both learned that manipulating octaves is not always a good idea, especially when you share the same keyboard with somebody else. Since the bass A in Vidas range stopped working, sometimes he tried to play both hands an octave higher, unfortunately that was a very bad idea, since I also had to play somewhere. By the way, Vidas managed to improvise registrations and to leave the 1st manual for the left hand which had all keys working.
The last and the most important thing was this recital confirmed once more that breathing is the decisive factor for giving in to panic or not. In all those horrific moments I kept reminding myself to breath and actually it helped me not to stop and not to panic.
The best thing about this recital was that it eventually ended and our listeners haven't noticed anything. Only our colleague who listened us from the nave noticed that something happened to the organ. But even for him this incident haven't ruined an overall positive impression.
One more time I learned that an organist must be ready for anything and everything.