Your impulse to stumble up to Idris Elba in the men’s restroom and challenge him to a dance-off is a bad one, and you must learn to control it. The Star Trek Beyond actor visited The Tonight Show last night to show off his fancy footwork, explain the humiliations of DJ-ing, and discuss his role in Macklemore and Ryan Lewis’s “Dance Off,†but most important, he calls you out for your bathroom-dance proposition. How and where would you two even dance in a men’s room? Your elbows would be slamming into the stall doors, your feet flying into the urinals. God help you if Idris Elba slips on some hand soap and gets hurt.