Having a senior engineer with a lot of context is worthless if the work environment does not promote open communication. You don't want to be the senior engineer or leader who shows "poor judgement" by opposing the mercurial owner "for no reason" if you're overridden and the feature launch succeeds without a glitch; no one gets fired for implementing a request that came straight from the top.
This is why non-rushed, scaled roll-outs are essential for large system: had they tried this on 1% / 5% / 10% of random traffic first, they could have caught this. Yet again, if the directive to roll it out to production came from the very top, you set that gate to 100% immediately.