Or when working on massive infrastructure like this, you write plenty of tests that would have saved you a month worth of work.

They write reordering, push it and glibc tester fires, fails and you quickly discover "Crap, tests are failing and dependency (glibc) doesn't work way I thought it would."

I suspect that if you could save them this time, they'd gladly pay you for it. It'll be a bit of a sell, but they seem like a fairly sensible org.