The usual bunkai that is taught for escaping the arm twist (after the nukite) is to turn into the twist and deliver an elbow or as the kata has it a tettsui. Is there any other bunkai for this move? Years ago I visited a shorinji kempo dojo in Japan and they were doing escapes for this move...I did the stock bunkai from heian sandan and the sensei freaked. He showed that by doing this the potential for putting strain on your right shoulder is huge and can be very easily increased by your opponent simply by lifting your right elbow higher.
Caught early enough (ie while the opponent is in the process of twisting your arm) the bunkai works, however once in the position (with your arm behind your back) the bunkai becomes problematic.
My frustration is that for the life of me I cannot remember what he suggested as an alternative.