I tried flying indoors once. In a church, trying to get a short video for their web site. Blew the altar cloth off the altar and called it quits. As a joke I suggested to our priest that I would do one more video but during a mass. Told him he would have to wear a hard hat
With modern drones which claim 360 degree sensors and obstacle avoidance it should be theoretically possible to not crash into things.
flying in a church sounds like fun. sign me up! but there will be damage.
when you fly several drones in a room that's 12 ft at the widest with furniture (or cardboard boxes as furniture like obstacles), you only get beeping because something or someone is always danger close. we turn the obstacle avoidance off so we don't have to listen to it. i do not do any of this or recommend any of the things i've done at work with your personal drone. i also don't use my personal work drone (mavic 3) to train indoors, but instead i shared a very old fleet phantom 4's with other pilots. when we were seriously training with the intent to get through a house, we used the mini 3 and called out our movements.
we learned to fly indoors at our state fire school. they didn't realize how much damage there would be to doorways and picture frames, and they have a lot of classes that we would disturb if we flew there often, so we built an indoor obstacle course inside a pole barn. there's a paratransit bus to fly through (2 open doors and 1 open window with all of the seats intact) cause the drone manager has seen way too many cop/military movies and just knows we'll have to make entry on a public bus someday. we have a crudely built set of stairs to nowhere with a 180 degree turn halfway up and the second half of the stairwell is covered at waist height to make it more difficult. there's a doorway underneath the stairs to practice flying through. apart from that there are road barricades set to different heights to fly over and under, several long black corrugated plastic tubes and hanging tires to fly through. some of the tires are hanging parallel to the ground so you can fly up or down through them. there's a makeshift hallway with turns that's made out of tarp that kills most newbies because the props will suck the tarp in. and a cage at the end of the hallway with holes in the ceiling that you have to navigate out of but can't use the camera to line up since it's overhead. there's some open metal shelving at the far end. some of the shelves have plexiglass bolted to the front and some have mirrors on the backside. we move them around so nobody ever knows what shelves are open. it can be disorienting. the obstacle course can be more challenging than a house because the spaces are tighter.
there are also buckets in various places (like inside the hallway) with pictures. we swap the pics out from time to time so we can verify that someone completes the obstacle course and doesn't just memorize the pics. we also have a bucket tree, it's a 4x4 post with 4 buckets bolted upside down at a 45 degree angle from the top and 4 more at a 45 degree angle on the bottom. you have to do a donut around the pole while keeping the camera pointed towards the pole and pointed either up or down to see the pics inside the bucket.
we use mavic air 2 drones for the obstacle course. they've been abused and we rarely change out the props. but they're still flying. while i've learned a lot flying for the state, i don't really use any of that when i fly my drone. i fly out to whatever i'm shooting, mess around until i find a good comp., take the pic and fly to the next shot or back to where i took off. i always fly with the nose forward, even when returning to home, like i learned at work.
if any of you want a burner drone, look at the original mini. we were looking at them at work the other day as a single use drone, they're going for about $300 on amazon. our big problem is funding. we can buy all of the accessories we want with grants, but grants only cover actual drones on the blue uas list. dji is not on the blue uas list. none of the drones on the blue uas list are anywhere near as good as dji drones.
