I can only assume he is taunting off of you. If you have JoL up, I can't image them catching you in a regular race.
To put it in perspective: When we first started raiding, the first day in OS I would see if I could pull off our bear on the two mob pulls. He was MT in almost entirely Heroic epics. I was OT in mostly heroic starting gear (22k health, 540 def, not a lot of avoidance). I did two OS runs with the bear with that gear level, and probably pulled off him a handful of times when I tried. He never succeeded(without taunting) when he tried the same. More recently, with me in Heroic Epics, and a warrior tank, I was pulling off of a warrior in t7 gear.
Keep in mind that this is with JoL up, so the situation won't hold true when (if) 3.0.8 ever comes around.
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My blog of my experiences leveling a tankadin.