- Ultimate responsibility for ensuring all documentation is correct?
- Ultimate responsibility for ensuring back-up work (including testing regime)?
In both cases it's the CTO's job.
If the tale had stopped before it got to the bit about the new chap being fired I'd have gone with "No-one, it was a wake-up call for everyone." Even C level folks are only human. Things can get over-looked; over-reliance on assurances from the management chain can combine with a monstrous workload to help this along.
But it didn't stop there. The actions of the CTO tend to suggest someone lacking the emotional maturity, willingness to take personal responsibility and with the primary desire of covering their own behinds at all cost to ever be trusted with that responsibility.