Mike isn't rattled. He's being a duck and trying to set up a fight with Weidman. Why? He knows he'll lose to Romero. He knows he'll lose to Whittaker. Weidman is a good fighter, but he thinks he can beat him.
Weidman has taken a lot of damage from Machida, Vitor, Rockhold, Romero and Mousasi. His chin has potentially been cracked. He also has terrible striking once the TD threat is gone and awful cardio.
Bisping has solid striking, great TDD and a high level cardio. What we are seeing here, is Bisping trying to hang onto his belt.