Going positive is in fact impossible as he'd be making 1 or 2 damage depending on range. So you're saying he needs to pop the last couple ticks off someone's healthbar at least one more time than he gets killed every single match. Maybe asking too much don't ya think? Getting positive scorecard is easy, it's called being carried. If you want to see what it looks like being lvl 20 in non-ordinary crucible he did this exact thing in iron banner.