He has a PhD...
A woman I once knew told me this story. Her friend was a single mom while in grad school, when her water broke she took herself to the hospital on the bus... After she finished her PHD she was unable to cross the street without help.
Getting a PHD on a topic does not grant you some immense skill with said topic (it can...)
However you should have done the following:
1. Production comes first, if you CAN fix it, do it. Production problems are the only time when you can and should be the HERO!
2. Once production is fixed, THEN you give the person shit... and the way you do that is by making them CYA --- your PHD should have been writing the same test for EVERY public function in your system to catch the mistake for as long as it took.
3. Its a job, you don't have to be NICE... however being an asshole isn't going to get you anywhere.
4. If you have to put someone down, at least be funny about it, or try to be. I used to work in an office that had "tokens of shame" (beanie babies). Someone would mess something up, and the token would sit on their desk, till someone else saw fit to "pass it on" to the next person who dropped the ball. The other favorite is "I'll bet you a dollar this is your fault" of course no one ever thinks it is, and they take the bet (you have to get dollars out on the table) --- then when you show them make a big show of taking the buck.