https://coalregioncanary.com/2020/11/26/pennsylvania-election-mail-in-vote-spikes-expert-testifies-senate-hearing-gettysburg/
This appears to be a more detailed version of your meme's topic, so lets go over this again with full context.
Already, Col. Waldren here is on shaky ground as, like you, he is using the word impossible but according to his testimony, he is under the impression that the time it took to process this number of votes, by the machine, was impossible as it exceeded the machine's capacity and ability. Which, if this is true, then he is CORRECT to use it here, but that doesn't mean it is impossible for Biden to have won 99.44% of the mail-in ballots in one dump. It is impossible for a machine to process faster than it's ability. If it did, in fact, do this.
In the abysmal interview with Giuliani, Waldren explains further that a big spike is a "prime indicator of fraudulent voting." But a few seconds before that Waldren explains that he and his team understand the spikes not as evidence of fraud in and of themselves, but as red flags: "These spike anomalies in this chart really show where for us to look forensically to actually determine what happened with these votes." And a few seconds before that (at 1:28:00), he says, "Really only a detailed forensic analysis of the actual machines and software will truly show how many Pennsylvania citizens have had their civil rights violated."