When Her Pickup Runs Over Your Dog

I’ve never encountered this before, so I really could use some guidance. I have a project coming up soon where the person I’m interviewing on camera may not be completely thrilled about some of the issues we’ll be covering, ranging from the slightly awkward (showing up wearing the same novelty t-shirt) to possibly litigious (her pickup ran over your dog). Any tips or tricks for keeping the speaker on track even when they may not be totally happy about where the conversation’s going?