If you feel the need to leave an interview early it's best to do it in the least rude manner possible. Unfortunately, someone is bound to see whatever you do as

If you feel the need to leave an interview early it's best to do it in the least rude manner possible. Unfortunately, someone is bound to see whatever you do as rude to some degree, so be kind, and courteous, honest and polite. Explain to the most senior participant possible (such as the hiring manager) or barring that someone from HR why you are calling it off early. Don't get huffy and spew on the staff as that's needless. Culture mismatches may not be obvious to young inexperienced staff, but to management it's an obvious red flag for team work. And it's management's job to keep the team highly functional so they will thank you for your honesty.