Its called a tank pull count down, Pulling 3...2....1... now, at the " now part i've always popped my potion of speed for a pre-pot, and rocketboots to the boss with trix already going on the tank, i get maybe 1-2 seconds not having overkill, but i get 15 seconds of potion of speed, and im attacking the boss sooner, which has always been one of the top ways to out dps people.
So you start with mutilate out of stealth? I hope you don't run straight to the boss smashing mutilate, do you?
Coz' if you do open on the boss without stealth I suggest you take a closer look at the talent you have to put a point into in order to get mutilate (Overkill). Anyway, You do know that there's an ability called Sprint, right?
I'd rather save sprint for some important part of the fight. What I tend to do is: Stealth, finger over my speed pot button as close as i can be to the boss. On the countdown to pull, at 3 tricks, at 1 speedpot (thus removing stealth), then haul tail to the boss. If it's a boss like anub, i'll for sure burn sprint, but some bosses are close enough to just run at. Anyway, the point sits that mutilate does more damage per energy than garrote, and provides a load of combo points making the early part of your rotation easier.