My understanding is you are correct that we cannot enter, however I would suspect it started as a 911 call of a fire outside the consulate by some random passerby watch got the response going to the scene and only then did they discover what was going on.
You missed my point, which is:
The Chinese know that if there are hostilities diplomatic protocol becomes null and void.
So the question again is ....why?
It could mean their primary equipment to destroy documents is out of service, or it could mean something much more sinister.