I have flown my MP indoors so here is my 2 cents worth:
- Pick up a set of prop guards. They are inexpensive and will help reduce the pucker factor flying indoors.
- Use Tripod mode.
- Set RTH to hover.
- Turn off collision avoidance sensors.
- You may also want to turn off VPS. While it may be helpful holding position I have read (but not tested) that if VPS is left on it will limit how high you can fly without GPS. VPS may also cause an unintended movement up if you fly close above something.
- Stay at least one foot away from a flat ceiling. If you get too close it will suck itself up to it.
- Take off the props, fold in the arms, and use it as a hand-held video camera. This will get you the 3-axis stabilized camera and the video quality should match your flying video in editing.
- The props cause a lot of air movement so stay away from drapes, papers, or other light items and stay away from the floor. You will find out pretty quickly how much dust and other debris are lying around. If you have ever stood directly under your M2 while in a hover you know how much air it is pushing.
- Walk directly behind it while flying. It will keep you out of the shot and your flying directions will match your left/right stick movements.
- Be aware of reflective surfaces. Nothing like a shot being ruined by the operator's reflection in a window.
That may be more like 10 cents worth but it is all relevant.