If access to the site is unsafe and thus the site is closed; not having access seems reasonable.

Time services are available from other locations. That's the disaster plan. I'm sure there will be some negative consequences from this downtime, especially if all the Boulder reference time sources lose power, but disaster plans mitigate negative consequences, they can't eliminate them.

Utility power fails, automatic transfer switches fail, backup generators fail, building fires happen, etc. Sometimes the system has to be shut down.