Collider in RCT Subgroup Analysis

I think this is quite logical but I am sure there will push-back on both gating and the concept of prognostic vs entanglement with the treatment mechanism since the entire current view of subgroup analyses is purely external to the pathway. Perhaps your paper will begin to change this view but I must confess that it is a difficult area to grasp and until I began to question mediation / subgroups I did not fully appreciate the concepts you have been raising for some time. Now it all finally begins to make sense.