This is a major cutscene.
After beating Memory Evaluation, a cutscene featuring the Gentleman will begin. He is standing at the beginning of Memory Evaluation, part 1. He describes the tunnel, saying it was made by an expert (him). He continues, saying that the first half of the tunnel lets you study the configuration of the tiles before being plunged into darkness. It is then revealed that it was only a rehearsal to the Lizard, who is asked if there are any questions. The Gentlemen then responds to this by saying (to himself, really) it was wishful thinking on his part and cannot wait for the return of people who can speak. At the very end, he starts over in rehearsing his speech to the Lizard.
After unlocking this cutscene and the Superpowers cutscene, the Coordination Challenge tunnel will be unlocked.