There are a number of ways to train transitioning drills. Moving from our rifle to our pistol. A lot of them involve setting up the drill to consciously work on the movement. I agree there is value in that type of training, but I like to set up the opportunity to do that training in a more organic way. What do I mean by this?
We set up our target(s) and work on our rifle drills. And as soon as we have a malfunction or go dry, we immediately transition to our pistol. This adds another layer of training to our trip to the range.