Be sure to attach prop guards. One "trick", the Mavic will always go sideways as there are no sensors there, so if one treats the sideways as forward, one can go anywhere. Bad news is that one can go anywhere, thus the prop guards.
My second flight indoors went well. I was tasked to hunt for a boomarang on top of some office built-ins. Didn't realize how much dust, cat hair, loose papers, etc, fly around in the prop wash. The video clarity is incredible for such a small aircraft. A larger drone would have not been practical in such a small space.