Like what Quote and Geez3r said, I'm fine if The Vestige never really succeeds in a meaningful way. As long as my actions serve to heighten the heroic nature of the heroes I'm fine with that.
As for my first two examples, I was trying to focus more on having those just be situations. It would be up to the heroes if things go as planned or they save the people or themselves.
As I said earlier:
In short, villains (especially arch-enemies) should serve as a foil to the heroes so that they shine all the brighter after having faced difficult and sometimes overwhelming odds and staring into something of their darker selves.