So, i'm thinking of a story and i need some tech info.
How risky is to de-solder an usb plug if the flash-drive contains important files? It would be relatively safe for someone capable, or the heat is way too risky for the chip/content?
Also there's any (MacGyver like) way to quickly access the file or reconnect the plug without a solder while only having access to office supplies?
Office supplies? I think it is plausible but far-fetched - depending on the office.
Quick? Likely? Easy? probably not.
I assume you have enough scissor and stuff to open it and get at the PCB.
Any good MacGyver these days has a TS-80 style iron in their pocket - but if not they might bodge together a soldering iron from any heater / kettle / hair dryer (bathroom hand dryer) or even just some electrical resistors.
Shave down any copper wire thin enough and you get a heating element that will work for a short period of time - the solder just has to melt before the iron does.
Marry the heating element to the right size thermal mass tip, to allow it t get to about 350 degrees C annd deiver enough heat to melt the blob. you also need a heat proof electrical insulator to isolate the tip. I think ceramic usually, a Kettle heater will have something like that.
MacGyver can do thermodynamic heat flow / heat capacity calculations in his head anyway so the tip design is no big deal - in reality trial and error at this step is where you run out of time and materials.
Alternatively, maybe hack the laser printer, it's probably not hot enought ootb, but if you can manually cause the laser to dwell until the solder melts it might build up enough heat? - it only needs to work for four blobs of solder anyway.
Once you have the heat source sorted out, you need flux to reflow the old solder that's on the pads. I think vaseline / petroleum jelly will work in a pinch. Some office worker, or even first aid kit might have that as lip balm or something. The HQ of Deus Ex Machina Ltd. has a pine tree in the atrium with some rosin seeping out of the bark.
Anyway, with the heat and flux sorted you just clip the tail off a usb mouse and solder the wires on to the PCB .