Just to add my own 2 cents to your comment:
Quote:
it boosts one shot. Only One.
Unfortunately, no you're wrong. There is a bug with this ability that I'm surprised more people haven't discovered. The buff applies to any shot still making it's way to the enemy, it does not apply to the shot after it's fired, but the shot that connects during the time period your buff is up.
So you can in fact, used Aimed Shot followed quickly by an Arcane Shot and receive the Rapid Killing Buff for both shots. I use this exclusively to 2-shot lower lvl enemies. Aimed Shot can crit up to 3.5K+ and Arcane can crit for around 1.5K, dealing roughly 5K Damage in a very short amount of time with the Rapid Killing Buff. To me it makes grinding and farming so much easier.
The only problem with this bug is that you need to be farther away from your next target, to allow both shots to be fired before the first one reaches the target. In otherwords if you're 5 feet away from your target, it will take all of 1 second to hit, but if you stand farther away, you give yourself time to fire off that 2nd shot before your first one hits.
But to get back on Topic, I agree with NorthAI it's all about the 2 minute reduction, the added damage is just a bonus.