I hope this isn't a disappointment as this is the principle of a novella - unexpected and yet justified end. So it all was done well - within the genre where if you think about it you as a writer don't have that much of a freedom. The story begs a boolean outcome: a man either going to be praised for his ill-doing or punished. Any other resolution will be anticlimactic. For example, if he'd be hit by a car. This could have happened in real life, but in a story, this makes no sense.

So again as a writer you are down to two possibilities. Which one to pick? A broad audience reader is already sedated enough to expect that the male character will succeed. So it's the time to strike a blow - the option #2!

The rick is to make it in the way that it is justified. The reader should say "How could I not see such an obvious thing" rather than
That couldn't have happened." You've done it well. So be proud! )