The interviewer would like to know how you go about making decisions on your own when a supervisor is unavailable. Are you okay with making independent decisions? Tell the hiring manager about your confidence in your ability to make the right decision, on your own.
"If I needed something immediately and my supervisor was unavailable I would make the best decision possible, keeping in consideration what would be the best for the company. In my current role, I receive a lot of autonomy and am comfortable making decisions on my own."
"I feel that when I am confident in my knowledge and have a full understanding of the result that my employer is looking for, I can make educated decisions when left on my own."
"I am accustomed to working on my own and taking the lead on projects. I am certainly confident in my knowledge and ability to make the right decision when left to make it on my own."