Audio problem: Towards the end of Lex telling Clark about his car, that it was stolen and returned, Lex says "Often that can be the test of a true friendship." After Lex's line the camera switches to show a reaction shot of Clark. In that shot, just before it switches back to Lex, you see Lex's mouth move as if he is saying something but there are no words heard.
Smallville (2001)
1 audio problem in Velocity - chronological order
More mistakes in Smallville
Martha Kent: Clark? What are you still doing out here?
Clark Kent: Well, I'm still doing my chores.
Martha Kent: Well, you usually finish those in about two minutes. How is it that I drove to Metropolis, attended the Children's Foundation dinner, and made it back before you finished?
Clark Kent: Because I'm doing them the normal way.
Trivia: When Clark confronts the Flash in his hotel room, he reads off the fake IDs Jay Garrick, Barry Allen and Wally West. Those are the secret identities of the first three men to be called the Flash in the comics. Also, this Flash says his name is Bart, like Bart Allen, the teen hero formerly known as Impulse and currently being called "Kid Flash." (00:10:35)
More questions & answers from Smallville
Answer: No, there is no such character in the comics. He's a "meteor-freak" like all the other baddies on the show. The sound has something to do with him vibrating his vocal cords very fast to create a high-pitched squeal.