Sì, alla white room arrivavano due tubi, quello di sopra ospitava il “carrello” che trasportava il personale in condizioni normali. Il tubo di sotto è lo scivolo di emergenza.
Nel libro sopra citato, alle pp. 192-194 si legge:
Running from the access arm were two pipes leading to two separate underground rooms. To board the orbiter, the crew or launch pad personnel rode on special trolleys inside the top pipe. The trolleys could accommodate about a dozen people. The lower pipe was a giant escape chute to be used by the crew or personnel in the event of an emergency, with a special mattress in the underground room softening their landing. Once there, they would have hermetically sealed themselves in an adjacent blast room where they should have been safe from explosions, leaks, and the like. A special test stand imitating the chute was built in 1986 at the Scientific Research Institute of Chemical and Building Machines (NIIKhSM) in Zagorsk, north of Moscow. The chute at the pad was tested numerous times by engineers. It was reportedly also a favorite playground for off-duty soldiers in the evening hours, as evidenced by the numerous boot imprints on the mattresses.