If nothing loads nothing gets cached and you can get in a cycle of very slow 404s.
The current abomination I'm working on avoids this by caching the errors and serving them for several hours...
One of the worst outages I witnessed was due to negative DNS caching on the most outer router that took the company a few (3 or 5) working days to fix *after* issue was identified.
Is this a designed self-cache poisoning? Abomination indeed.
They should have called it upgraded performance. The 404 page loads blisteringly quick!