Which lines in this excerpt from Arthur Conan Doyle's "The Contest" suggest that Emperor Nero was ruthless?

The line in the excerpt from Arthur Conan Doyle's "The contest" which suggest that Emperor Nero was ruthless and the line is this one "Quick, Policles, quick!" he cried. "My pony is tethered behind yonder grove. A grey he is, with red trappings. Get you gone as hard as hoof will bear you, for if you are taken you will have no easy death."

"No easy death! What mean you, Metas? Who is the fellow?"

"Great Jupiter! did you not know? Where have you lived? It is Nero the Emperor! Never would he pardon what you have said about his voice. Quick, man, quick, or the guards will be at your heels!"