From the pits of hell itself, and the individuals who brought you Kraft dinner, we are glad to inform you of why MC 4056 can not be found.
It was a fine sunny day on the top floor of the MC building for Miss. Ng Pur Sonnes in 1967 when suddenly, she found... a fly in her purse! Unable to see clearly, she headed over to MC 4056 and proceeded integrate in the sunlit room when dinosaurs arrived and swallowed her and Max Ferrol Claire the First (aka MFCF) whole. Max, who was indigestible, was found later that week in Columbia lake unharmed. (This was clearly before the killer bees had destroyed the lake).
Later that century, just before Robbie Burn's day, Soup E. Stitious was struck down in his prime. Struck down in his prime, man! And without ever having caught the Trix Rabbit. I mean come on man! Have you no morals? No pity?
Shortly thereafter, the geoengine.math machine, located in MC 4056 was tortured by deep frying. As the cheese oozed out of it's ports, it was heard screaming as MFCF drove out of sight.
MC 4056 is a prime number divisible by 13, and therefore unlucky. The room was never built, for this reason, just as the elevators in the MC do not go to the 13th floor.