Although I agree that it would be seen as an escalation, it would fit the bill of Putin's and Lavrov's comments over it being a valid reaction, without necessarily striking into actual NATO territory.

They can also send multiple clear warnings like they did last time so that the embassies can evacuate personnel again, in order to prevent foreign (civilian) citizen deaths falling solely on their hands. But then NATO chains of command need to also act responsibly and allow personnel to evacuate, which is much more likely than it seems, as they did evacuate a cease functions temporarily just last week.