I dunno if it offers any comfort, but we all come from a long line of lightly singed ape things who've learned to run fast from fire even if we do play with it. Seriously, it's all pretty automatic. First fire, without even thinking, I managed to get the cat carrier out of the closet, stuff two cats into and get out the door in not much over a minute. It wasn't until I got out that I realized what I'd managed to do. We've got some pretty efficient schema to let us do what needs to be done.

Also, if the computer room is a problem, then mount a fire extinguisher right near the light switch. My own experience with free standing electronics is that the fire goes straight up. Just give it a clear enough path and you should be good to go. Seriously, all the prep you really need to do on that score is just keep the papers away from the ignition sources.

I learned all about this in my college lab electronics courses. Generations of previous students had bypassed the fuzes on our breadboards with solder for some reason. We started to do some fairly high current projects for the op-amp section and more than one of these things went up in smoke. The fire was pretty much a straight line up. Same thing when the transformer on my old vacuum tube amp went up. That one was my fault. I bypassed the fuze on that because I wasn't sure where I could find a replacement. Lastly dust is not flammable as the salesman might make it out. Household dust is largely stuff like dead skin and fabric lint. These things need a fairly high energy input to get going and unless there's more easily ignitable fuel laying around, it'll smolder itself out. If you work in flour in the study or do routing(the woodworking kind), your dust hazard is not too severe.

Flour by the way is a great mad scientist sort of thing. A tall building, a sack of flour and an oil soaked rag makes a nice fireball.