I have a chance to fly in a gym over people training, it could be very cool. But obvious questions on flying come up 1 I assume GPS doesn't work, does this also mean home lock and course lock can't be used? 2 I assume atti is the only way to fly besides manual, (which I haven't practiced) 3 does the iron frame of the building screw up the compass? Does that matter? I think it would be a blast to fly in a big space with no wind and have long smooth shots but safety of people and equipment is obviously the issue. Anyone have experience with this?