When the Mavic was unveiled. The CEO or whoever it was, doing the Steve Jobs on stage unveiling, focused mainly on its ability to track subjects, recognize gestures and hold position indoors. So yeah, yeah u should be able to fly indoors.
Set your max height to below ceiling level
Set all emergency responses to hover or land
Disable return to home
Make sure all obstacle avoidance sensors are on and functioning
Raise lights to a level that doesn't result in a low ambient light warning
Watch for backwards and sideways drift, there is no obstacle avoidance those directions. Be sure to disable backwards flight in intelligent flight modes.