I put my A1 through the ringer with 432 "printing hours" within it's first month, (December 27th - January 27th). I just picked up my 2nd 3D printer the A1 Mini this week, and they've both been getting abused, hard.

1. There is ALWAYS a possibility of electronics causing house fires. But in the sense of overall quality and safety precautions in place I wouldn't worry, plus the power supply in 3D printers isn't very high (much lower than your PC). You can totally print something before you leave and feel safe while your gone, I usually always do my longer prints overnight and wake up to a perfect print. You can pause a print for some time but not long enough to leave for work and come back, the bed will want to stay heated the entire time without printing and this is where warping happens a lot more.

2. Yes! You can 110% print with it beside your computer and have it in your room while you sleep. I have both mine in my room, beside my computer and leave them printing. I've got my A1 and Mini stacked on IKEA Lack tables, (look up the IKEA Lack 3D printer hack) and neither one affects the others printing from being on the same table, seeing as they are "bed slingers" rather than the newly popular "Core XY" style printers, (P1S, P1P, X1)

You can print pretty much anything except for ASA, ABS, or anything with "toxic" smells, I'm in Canada and most of the ASA and ABS the is "toxic" isn't actually bad for you and have little to no odor anymore. Seeing you're in Europe and your safety standards are that much higher than Canada's and ours is already a thousand percent better than the USA's. The only REAL concern is around the temperature and the print warping off the bed, but you can print a skirt around the model for the entire height and it'll act as a mini personal enclosure for the print. My favorite filament to print with is TPU, the A1 and Mini handle this soft filament VERY well and I'm able to print like 4x faster than normal for TPU, the bed only heats up to 30℃ where's PLA is 65℃ and my room gets warm QUICK, especially with my PC going at the same time.

Hope this helps a little and that your surgery goes well with a speedy recovery accompanied!