All character models walk and run at the same pace. As a tank, you're only choice to move away from something "faster" is to use sprint (thus draining all your TP). I honestly have no idea if there is a potion or other consumable that can help out. I stopped leveling alchemy at level 29, though, and haven't browed the market board for potions in some time.

Sorry hear about your lag. I'd suggest to keep moving a little side to side (even if it upsets any melee in your group) to give you a slight "jump" on moving out of the red AoE cone or circle.