I agree it’s an urgent (and emerging) situation.
I am however of the opinion that any heroic effort to formalize specific details via Big Consensus (which would take at least 2 weeks to “do right”) at this point seems secondary to just doing the needful (locking NB down as necessary, and opening it up on a case-by-case basis).
If I might suggest using the power of Big Consensus for a more flexible arrangement over the coming months, hopefully not longer than a year - to delegate a “Ministry of Defense Against Contagion” or whatever - with a smaller group of people trusted to get the details right from an informed perspective of Excellence and Safety First. Personally I would be comfortable seeing some “safety veto” superpowers (temporarily) granted to this group.
So the necessary bikeshedding for some alternative Big Consensus proposal along those lines would then be more about establishing this general framework for specific EMERGENCY COVID-19 SAFETY MEASURES to be determined on an ongoing basis by a shadowy
cabal Guild of NB insiders. (What could possibly go wrong? This will be an interesting discussion, to be sure. Solvable problems I think, if there is a thoughtful process to appoint and if/when necessary also remove any specific individual “decisioneer” from the Ministry of Contagion - if they turn out to be excessively corrupt or certifiably insane in the membrane or whatever.)