Let me describe what I mean by emergency in hymn playing.
Imagine that you have to prepare four different hymns for the next Sunday. You have seven days to prepare and you‘re starting to practice these hymns in four-part harmony. So you‘re using this usual technique to place the tune in the soprano with the right hand and then you play the bass in the pedals.
You perhaps add the alto line in the right hand part and even the tenor in the left hand so basically this is a complete four-part harmony. You‘re playing from the hymnal - you‘re not harmonizing the hymn tune in four parts. Although there are a wide variety of techniques to perform hymns, this is a normal and usual way of playing hymns on the organ.
You have seven days to prepare for the church service and, of course, you are very confident that you will be doing well for the next Sunday. Your have a plan of action for every day of the week and you are starting to deal with these hymns in the usual manner as if they would be short real organ compositions.
By that I mean you would take these pieces apart and practice line by line, then two lines at a time, four lines at a time, then the entire hymn from the beginning until the end without stopping in a slow tempo. Also you work in separate voices – soprano, alto, tenor, and bass alone. Then you practice all kinds of two-part combinations, later – three-part combinations and so on until you are ready to play the entire four-part texture.
Everything goes well according to your plan but during your practice session on Friday or Saturday evening you discover that you are still making quite a few mistakes. You are beginning to realize that you will not be ready to perform these hymns in public fluently and without mistakes tomorrow after all. The anxiety level increases and you might even have trouble sleeping that night.
If you want to find out how to deal with such stressful situation and still play fluently on Sunday at your church service, watch this video.