Waling dead is a show that usualy pays fairly good attention to detail, but the scene in Too far gone where it was used was complete bull crap, there were tons of flaws in that scene that led to it being destroyed, First off, the driver as far as I know was a tank driver in the military, so he would of had to go through rigorous training to know how to operate it, that means he's smart enough not to roll the tank within spitting distance of ricks group, that thing could hit a moving target from over 500 yards away, also from the look of it, the tank wasnt firing high explosive shells, if it was, the explosions would have been much bigger and much more violent, also they tank would have shot the group shooting at it behind the van right of the bat, not to mention the tank was equiped with a 12 mm anti aircraft gun that wanst present on the tank, also that big bulge on top of the tank is a commanders cupolla, pretty much a 360 degree window that allows the tank commander to make sure the tank doesnt get rushed, so derryl wouldnt have been able to get close enough to use the grenade to blow up the tank so unless the driver was a complete moron and forgot all his training instantly, they should have been able to take the prison without any trouble