1. Never looked into this myself so I have no idea.
2. From what you've described you're probably better off using omni-directional wheel-based systems to roll over the ground along sensor tracks embedded in or under the floor for devices to guide themselves along. For anything travelling along the ceiling, have ceiling rails. Using maglev for this kind of thing would require stupidly huge amounts of power and would still be restricted to rail-like envrionments anyways, since if you free-floated something entirely you'd have to have precision control over the amount of electromagnetic power being applied in order to maintain a constant altitude in the face of changing weight due someone climbing onto or off of something, or even just removing or adding stuff to a tray, plus there'd be zero friction to hold such a thing stationary.
3. Degrees is irrelevant as you can alter aspect ratios. Standard 1280x720 resolution for 16:9 720p, regardless of framerate, is typically encoded with compression codecs running 4 Mb/sec. So an entire day's worth of footage would be (4 x 60 x 60 x 24) / 8 = 43,200 MB, which is about 42 GB. Uncompressed at 24-bit colour per frame at 24 FPS, you'd have 1280 x 720 x 24 x (24 / 8) x 60 x 60 x 24 = 5.214 TB
Naturally, you can use lower bitrate compression to consume less memory.
4. Turning the environment in a room into a vacuum to put out a fire would require the room to be air-tight to begin with, but at the same time anyone else in the room would be exposed to that and would likely be killed or severely injured by the pressure change. Star Trek TNG's idea of using forcefields to contain a fire is a lot more plausible since we actually already have forcefield technology* in the sense of being able to separate two similar envrionments without a physical wall between them, though it's been a long time since I last looked into it so I have no idea how far that technology has progressed. As for replacing the oxygen in the room with a gas that doesn't burn as readily, the same problem comes into play that anyone else in the same room is going to suffocate from the lack of oxygen and, if they survive, may be poisoned by overexposure to whatever gas the oxygen is replaced with.
* EDIT: Just did a bit of searching and the information I originally read about this and the video clips I saw over a decade ago don't seem to exist anymore and everyone says it's just a speculative technology so... could've been totally false stuff that got paraded around as fact at the time. That happened with TONS of things back around the turn of the century. :P
--- Kris Asick (Gemini)
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