Context is a big thing. For example, giving us more context would be helpful. You've mentioned elsewhere that you work in tech. Why is Cheney speaking at your work? Will he know who you are? What can you get away with asking him? How do your co-workers feel about Cheney? In regard to asking questions, what kind of outcome are you after? If you're after an answer that could be useful to you personally, you might ask a question that he's been asked before, but framed in the context of your own circumstances. If you're interested in asking questions for the benefit of others, then why not coordinate with those others so that the Q&A moves in the direction of most interest to the group?
I work in tech, but at a university, so this will be more open than just co-workers. He doesn't have a specific topic he's speaking on, either. The university's political union brings in speakers to talk on whatever they like, usually announced shortly before the event or not at all, they do that and tell their life story some and then have an open Q&A. So... Extremely open. Everyone comes through. In the last year I saw Rachel Maddow and Frank Abignale, Jr. in the same format there, and last month they had Laverne Cox come in to speak, and right before that Joe Biden was in there addressing a crowd.
That's a pretty cool lineup. I'm trying to find work at a university myself, for ease of access to these kinds of things, making connections and other reasons. Good energy around universities, usually. Given that you posted in another thread about making a hard decision, why not ask Cheney something related to that? As it's a university, I'm sure that others would like to get some perspective on what it takes to "make it" according to Dick Cheney.