I'm not sure if they even bothered to open the cylinder to visually check the contents. I would probably have done that before applying power and risking there being water inside.
Wasn't that why there was an extended drying time in a specialized oven before reading the chips? It wouldn't make sense unless they had opened the cylinders and taken out the cards holding the memory chips. I would think that the main thing holding the ocean out of the memory modules was a well situated O ring on an end closure.