This happened to me once, as in my first month at a new job, I came in one day to find I had caused a bug in production. But I hadn't deployed any software!
It turned out that the department had carefully orchestrated a system whereby all checked-in code would move automatically to alpha the next day, then beta, then production the next week. But nobody told me.
A manager there later told me, "If the code we write is strong enough, it does not need to be released--it will escape."
"You have 60 minutes to code a security patch for a vulnerable payment processing app."
"Congratulations, you shipped to a million people and saved the company from hackers."
I laughed pretty hard at that, and the "aggressive integration bit"...I'd probably leave if a company decided to ship something I coded in an hour in an interview.
Great description of surprise push-to-production.