I wouldn't think it would be a show stopper, guys with DUI's still get hired once and while, and this wasn't something that was directly your fault, nor was it a rule violation of sorts. In fact, you could easily turn this topic into a great interview discussion about level's of comfort as an instructor, and what happened to your comfort level after the incident with your next set of students. I bet your hands/feet were very close if not on the controls at all times like they were when you first became an instructor.
Although I wouldn't say this on an interview, the fact of the matter is, a student who locks up the controls will probably dent an airplane every time, and there is nothing you can do about it. My best example of that notion was something I was told early on in military flight school....If the student pushes the stick full fwd, there is nothing the instructor can do to stop him. Morbid thought, but for the most part true.

I think this incident is one of the perfect "tell me about a time when...." questions that you will be asked.