Zachary followed the other into the cabin. When he had been on deck earlier, Zachary had already scanned the cabin with his Divine Sense and confirmed that the weapons he purchased were indeed inside. If the other party had not brought them, Zachary would not have boarded the deck directly.
After the other party opened the case and looked at the filler material from the sea's surface inside, Zachary knew it must be the original packaging from the factory. After all, at that time, it would be quite difficult to recreate the sea's surface, not to mention the problem with the raw materials but the fact that it would be challenging to place a raw material processing plant at the Water Base.