Belowradar
Should you really be opening the doors in flight as part of a training manoeuvre ?
I don't think your insurance company would like to hear about that and I certainly wouldn't consider it good airmanship.
I have had doors come open in flight and it is not a situation that should be taken likely as there are demons out there ready to catch you out and ruin your day/life.
I would like to see where it is shown as part of a training syllabus !