Here is another example (time 1:25-1:35) of release#1 being used from an ushiro position - this time, uke has tori in kataude dori - a locked-arm come-along. Tori gets in synch with uke's stepping and steps away, drawing uke offbalance. To further disrupt uke's motion, tori "kicks" uke's leg. I use the quotes here because you don't really have to kick, just touch his leg to stop it and stick it to the ground. From there tori does a large release#1 motion and finishes with wakigatame.
We played with this interesting little tidbit during this past weekend's ABG.