I tried soaking the model in warm water, as suggested on the super glue manufacturer's website. No luck - either the water couldn't get to the bond, or the magnet was just wedged to tightly into the torso that it would not come out.
At this point, I decided to do something drastic:
Since I had not glued the front of the torso on the model, I was able to use a wire-gauge pin vise and drill in behind the magnet - pushing it out.
It turns out that that particular setting was simply wedged in too tight. Even when I went to re-glue the magnet in correctly, I had to use a bit more pressure to get it back into the hole.
I guess the lesson here is to always give yourself at least a tiny bit of wiggle room. It makes things easier to work with. Well, that and rubbing alcohol seems to work for removing super glue bonds between metal and plastic.