Mac obtained many stacks of TNT by using the piston duplication glitch. Since the dupe machine, almost every player on the server has at least a stack of TNT. However, having access to Creative mode, she now has unlimited access to TNT and other blocks.
One such example of Mac using TNT: Episode 304 - STOP MAC! Interactive videoThe Bed Stealer has guns in the Battle Bed that fire TNT. Mwa-ha!