@crowdcontrol
I'll take a shot to answer some.
Planning and the head start that the other team had. They could very well accidentally set the drop to uranium, plutonium, or even a fully ready refined demon core just because they are thinking about trying to stop them from getting a weapons grade item directly. Unless they wanted to completely camp the stairs, they couldn't intercept the villains. They also didn't know what laws they already broke so it's not like they could perform a citizen's arrest for the group just arriving on a dungeon floor.
Ideally, they would have just brought down Komugi to set the drops by dragging her through each floor without telling her anything about the possible bomb material. Though to be safe they would have to set all the way down to the safe floor not just floor 24 as the relative strength of the villain's team is unknown.
Mining detection was used when they were leaving but only one of the villains entering had mining, that one person stayed behind in the dungeon for a few days while the others just left with a case containing the bomb core. They weren't searching bags and cases for everyone leaving, so not going to have detected the core leaving. The mining user was later found as someone who used a fake identity to enter.
JDA and WDA run info sites which Kei and Miyoshi have been feeding information through Naruse to. Some of which was attributed and some of it was anonymous. Any dungeon party can provide information if they want. That data is public and I'm sure that people have downloaded the information from it to make tools with. We even get Miyoshi downloading the known skills list to check against instead of having to make many queries through monitored web portal when above ground.
MC isn't looking to get stronger; he's looking for an easy life. There's at least a concern on what will happen to vault if he uses storage. Can he have two storage skills? How would he direct items to vault vs storage if they have the same activation. Appraisal has only been found on the flying eye things at the manor; it's not a common enemy they face. He's already rejected taking a Darkness IV orb because he doesn't consider himself as a good caretaker for any animals. He's already the top ranked adventure with crazy stats, several magics he can use. What would be the reason to trying to gain more power when he's already the top? There hasn't been any serious threat since Enoki where he had to dump 100 into some stats to win.
