Another incident to consider is the previous "biological Chernobyl" from 1979, which involved a (drum roll) lab leak of Anthrax (https://en.wikipedia.org/wiki/Sverdlovsk_anthrax_leak). Incidentally, all investigation was blocked in that incident, and the government denied culpability until Boris Yeltsin came into power and admitted that it was caused by military development (of biological weapons). The lack of accountability and transparency with the international community in that incident is part of why Russia was able to get away with continued work on anthrax-based biological weapons even after this incident. It's also why we need to bring greater scrutiny to what happened here with SARS-CoV-2, instead of pushing it under the rug - these leaks are more damaging than nuclear weapons and need the same kinds of controls.