Made of Hyper-go-on, and a lot of it.
Mach One for funsies to debunk Infinite speed is the same as using it to debunk FTL, High Hypersonic, etc.
This is just in reference to his name/identity of being a casual Mach One-er. I mean, Sonic literally reflects a Cyan Laser blast with a shard of broken glass when she gets the Dynamo Cage issues later. Do we assume Surge's statement still holds weight? It seems to be hyped up speech more than anything.
Also, Sonic literally hands Surge her ass moments after that panel with a smirk on his face.
Except even assuming Sonic is like Rel+, this STILL would make no sense.
EDIT: Did NOT mean to triple team you with a response, I didn't see Omega's additional response