N. ampullaria should be fairly hardy if given decent conditions.
3 hours outside of the glass shouldn't be that much time, at least not enough to have any lasting affects on the plant, unless the temperature and light exposure was extreme for that period of time.
In my experience N. ampullaria would benefit from lower lighting than other Nepenthes, a high humidity and temperatures between 70-85/90 degrees, during the night and day, respectively. Mine did just fine with almost no feeding, as will most Nepenthes. However if you are going to feed it I would suggest smaller prey such as ants and the likes just to see how it reacts. If you are already feeding it broccoli with no ill effects then that it is just fine. One thing to keep in mind when feeding any Nepenthes any type of food is that you want to be careful not to put too much of the food into the pitcher as to create a growth in fungus or algae. I can imagine larger chunks of broccoli might do that.
That being said, even if you do put to much in, it's just a pitcher and it will always grow new ones.
Main things to keep in mind with ampullaria:
1.) Not too much light when young
2.) Never let dry out
3.) Keep warm for best growth, though it can slunk along in highland temperatures.