If this IS the work of a group rebelling against the government, you would expect that group to get a message out to the wider world about their activities and motives. That hasn't happened, so this is most likely a nothingburger.

If I was leading a violent insurgency against a regime with a reputation for cutting corners on basic safety, and had no qualms about the loss of innocent life, false-flag deadly "accidents" would be something I would consider.

To me, the idea is morally unconscionable, but I didn't grow up in Red China.