Ryuuko had to disagree with the assessment that you put more lethal traps deeper in simply because that was where they were likely to have harmed or killed someone with loyalty to your family. That seemed like the obvious place to put the nasty but not fatal defences. If you didn't teach your enemies that clandestine attempts to harm your family would be meet with extreme retribution, why would they ever stop trying? The information angle was still relevant if they penetrated so far, as well...

The sound of that first defence and the lack of triggering raised an interesting possibility.  There was no reason for anyone to interfere with the library defences... but if they hadn't meant to end up in the library in the first place...

"Could the misdirection ward have sent someone to the library?"