I agree, but that leads us to an immediate and entirely logical conclusion:
- In the Yasu story, the bomb is shown to be triggered in the gold room.
- Yasu learns that the explosives are wired and how they can be triggered, and Genji seems to know how often Kinzo considered blowing everything up himself.
- Therefore, Yasu knows where the trigger is and knows that it CAN be set.
- The bomb is set.
- Therefore either Yasu set it, or someone else set it.
If Yasu is aware of the bomb's existence and that it was set, taking any action as a culprit makes no sense. If she's aware of its existence but
not that it was set, that means the culprit solves the epitaph, every time,
and somehow knows about the hidden trigger. If Yasu is
not aware of the bomb's existence, that part of the Claire story and the Tea Party are lies.
Any way you slice it, we have a problem. If she knows and didn't set it and is the culprit, she's killing everyone for theatrics when a bomb would do just as well. If she knows and did set it, killing is too risky. If she doesn't know, the story is wrong. There's a way out of that, but it forces us to reconcile either that the bomb can be triggered in another way
or the true culprit
also has access to the gold room and sets the bomb him or herself every time we reach Oct. 5, but never sooner than that (or it would explode on the 4th/5th instead of the 5th/6th).
In most of these cases, Yasu is innocent.