Heh. Gotta love almost getting fired for being too good at your job. I had a very similar experience; I was working in a subsidized restaurant which wasn't making a whole lot of money. (it was part of a university, and there were 50 year old university policies that had the university paying way too much money for the place. And the members set all the prices by majority vote!) Anyway, we were woefully understaffed so I found myself being thrust into many positions I had no training for (like bartender, cook, host, maintenance - they had me fix a toilet. Like with tools and turning off the water to the place and stuff, instead of calling the university maintenance people for free.) and actually succeeding in doing what they asked me to do.
Which lead to my boss, on her 6th Rusty Nail of the evening (which she didn't pay for, naturally), taking me into the public lounge where at least 2 of the other employee's were currently working and explaining to me that if I keep doing all this extra work (which she was giving to me) that I'd have to be let go, because I was taking work away from the other people working there (who were being given their own arduous tasks to do regularly, and not given the chance to do mine). When she staggered off, one of the girls I worked with and I just stared at each other in disbelief. Three weeks later I found a new job somewhere else.
4 months later the place went out of business because we reached a magical threshold of losing enough money that the university legislation could be set aside and the restaurant closed.