User blog comment:NOS Sterling/Sonic Boom to be Playable at PAX Prime plus PAX Prime Updates/@comment-4892653-20140828232018/@comment-24111359-20140829200712

It's implied somebody was threatening him, "Why don't you come down here and face me!?" is something you'd use if somebody was making threats from afar.

Well why else would they not be face to face with him if they weren't avoiding direct confrontration?

It has to be either Eggman or Metal Sonic.