Sato walked through the door with no hesitation at all. Having come this far, turning back at the last minute was nothing more than making a dumb decision. In fact, he couldn't even retreat at this point as once a the main trial have been activated, there's no turning back again for the challenger unless they replenish the resources spent in doing so. As for the process of the resources, there was no need to say that the current Sato couldn't afford it.
As his entire being went through the door, Sato suddenly experienced a zero-gravity sensation as he felt himself become weightless. This feeling went on for 3 seconds and during those seconds, apart from feeling weightless, Sato could neither hear, see, smell nor feel anything. It was as if his entire being was shutdown; his senses going dark. This feeling was akin to being in a mother's womb; the only exception being the operation of one's conscious.
*Vroom*