As for Lionel, he wasn't either one of Chenglei's or Dyon's match. While Chenglei was a 9th Order 7th Stage Dao Formation expert, Lionel was only a 3rd Order 6th Stage Dao Formation expert. His cultivation was surprising nonetheless, but he wouldn't last more than a few exchanges with Dyon.
The problem was that Dyon was very good at reading people. He could see that despite Lionel wasn't even the slightest bit afraid of either Chenglei or him.
It made sense for him to be unafraid of Dyon considering he seemed to be a mere pseudo dao expert. But, for him to be unafraid and even dauntless in front of Chenglei made little to no sense. It wasn't as though they were friends… They had only worked together in the past toward mutual ends.