Let the interviewer know how you deal with a large workload, emphasizing your organizational, time management, and prioritization skills. Avoid indicating that you would try to delegate (that's not part of the job) or that you'd just "do the best I can."

"If I sat down to 1 million tickets, I'd start by taking a deep breath! Then, I'd focus on prioritizing the reports. I would organize them into categories like "Urgent/Requires immediate response," "Important/Reply today" and "Standard/Okay to wait until tomorrow. This would help me stay focused on working through the tickets in an organized way."