In fact, get a couple of extinguishers, one at each end of the shop, you never know, you could be trapped at the bottom and not be able to reach just one. The cooling effect of using it just might help you escape.
Another thing, if you are rebuilding, get your mains trip switch as close to the exit door as possible, or even outside, and of course a heat detector, not smoke, as you can easily set those off when you are machining and have oil smoke everywhere. I keep meaning to get one wired into my mains alarm system in the shop. I have done it in the house, but not in my shop yet. They are less than 30 squid and no batteries to worry about, and they set the whole alarm system off, not just a feeble beep.
Bogs