What kind of tank?, for running people down you really have to think about the tracks, now an american M60 is quite a tall tank, the tracks hold the main part a far way off the ground not good for people crawling away, you'd drive straight over them, as well as the russian T models, the Russian T55 perhaps as that was quite small, you'd have to use the tracks and believe it or not driving a tank is quite complicated, the best kind of vehicle would have to be and armoured car tho still even the america 'hummvee' has quite a height from the ground 16" i believe, tho dont quote me
I wouldnt use a vehicle as it's just not personal, it'd have to be an up close and personall execution, i would like to fill a victims mouth and nose with polyfiller and watch them suffocate slowley while it expands in there mouth