DJI hasn't made consumer drones with user-selectable Atti Mode for many years.
Atti Mode is what you have when your drone doesn't have GPS reception (and is unable to use the downward-facing sensors to maintain horizontal position).
Atti Mode =...
On a Mini4P Atti is only a mode that it goes into when GPS signal doesn't meet minimum requirements - AFAIK it is not manually selectable using the regular controller / software.
However that should not cause you great problems flying indoors IF...
As a photo journalist, you know this is volatile and things could go south very quickly. It's really a "risk/benefit" situation and only you can decide if it's worth it. If you go for it, I hope you get some great shots!
I'm not looking for trouble. I'm a news photographer and looking for a photo. This is my job (freelance, self-employed). I will certainly take pictures of the protest on the ground with my Canon, but showing the detention center in the background...