[ It's clear from how closely he listens, the resumed stillness where he sits slightly hunched on the edge of the couch, how fascinating he finds this as well. Things square up quite closely, despite the vast differences in method. The brute force elegance of machine and serum versus the absurd defiance of physical law that is the Flash. ]

Sometimes I wonder if anything really ever does get "undone."

[ Between the cesspool that is human memory and the chaos of living, it's difficult to tell. ]

No evidence. Nothing I can accept as such. Paraphernalia, no matter how compelling, can be faked.

But there is a metahuman whose speed can approach that of light, under the right circumstances. More than one. And like you, we have to rely on his word that he caused certain changes.