An interesting wager and I'm not entirely sure about how to proceed as I'm unclear about the nature of the interrogation. Ethics is rather a complex of many elements, and your scenario will require more details before it can get a good answer. Some things that are missing are, kinds of virute, and kinds of consequences. Also, the nature of temporality and eternity will have to be settled. Does your question assume that there is nothing eternal?
Assume for a moment that death is akin to snuffing out a candle - once your bodily functions cease, you are no more. Will you behave yourself prior to that event, or not?
I think you have answered the question. Anyone who hedges on the question of whether they would behave well without fear of punishment or expectation of reward really doesn't have any internalized moral compass.