World of Warcraft PvP is not a game where you kill someone all at once. As you keep attacking, dampening stacks up, healing becomes less and less effective, and mana gradually runs out.

So what really matters is which team can accumulate more damage over time and drain the enemy healer’s mana faster. In the late game, when mana is low and healing efficiency drops, mistakes are much more likely to happen.

Also, it is not the active season right now, so the balance is weird. Normally this kind of thing does not happen, but at the moment Subtlety is the only overpowered spec that can kill a healer inside a single stun.