It goes to show what SOLDIER knew and didn't back then, from the way Zack nearly chokes on his drink. Most of his missions had involved Genesis and Angeal after he was promoted but even he had his own run in with Avalanche.

"Geez." He coughs, patting his chest. "I'm really starting to wonder if I ever really knew what the hell was going on in that place."

The answer is no, Zack. You didn't.