That's not a problem with Scrum, it's a problem with your team. If you're doing a bug bash every sprint, then your velocity is already including the time spent on bug bashes. If it's not in every sprint, you can reduce the forecast for sprints where you do them to account for it (similar to what you do when someone is off etc).

If you're competing within the team to complete as many story points as possible that's pretty weird. Is someone using story points as a metric of anything other than forecasting?