Sounded like the change had to go out same day. You don't handle a short-term real deadline by slowing down a developer and releasing a candidate's code in production. To a lot of us, this didn't sound like an interview, this sounded like getting someone to do needed work for free. Yeah, maybe we're wrong and it really was a genuine interview question, problem is that's indistinguishable from the "free programmer for a day" interpretation.