Your question is Debugging a High-Stakes Failure. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
Tell me about a time you had to debug a difficult technical issue in your code or analysis under time pressure. Walk me through how you isolated the problem, how you communicated progress to others, and what happened in the end.