Something else to think about, you wrote about your handling of the gun initially as you were backing out of the doorway. I obviously haven't seen the course so I can't say for sure, but do you think you could have engaged those targets without stepping completely into the doorway? If you could have been back a little farther so even your outstretched gun was not through the doorway? That would not only save your from having to worry about what the gun is doing as you are backing out, but will save you the time it took to step in and then back out. As you are doing your walk through before shooting a stage, think about the fact that any barrel, doorway, or shooting port you stick your gun into, you then have to pull back out again.
Just a suggestion.