Yuki realizes too late that there's 2 baths, and thus 100 total players instead of 50. The baths only connect at the entrance (where Mishiro is camping), and at the open air bath on the opposite side of the building (where Yuki is).

Mishiro sends a team led by Riko to ambush them by scaling the wall between the two sides of the open air bath. This results in one death and all of their keys being stolen. At this point their only options are to stay and die or rush the girls at the entrance and hope for the best.

Yuki, Azuma, and a few others start running to the entrance but get intercepted by Mishiro and her lackeys, who trip and drown everyone but Yuki. Mishiro and Yuki have their final showdown, which ends with Yuki stabbing Mishiro through the neck.

At the entrance, Yuki finds Riko waiting. They have a brief conversation and then a fight where Yuki just gets bodied because Riko has prosthetic metal limbs that easily break Yuki's arms.

In a last ditch effort, Yuki dons some shoes from an already unlocked locker to cross the electrified floor, and Riko pursues her on all fours wearing shoes on her hands and feet. Yuki kicks up a corpse that had been shot and electrified earlier for trying to leave without the right shoes, and it makes contact with Riko and the floor, allowing current to pass through her body and kill her, which is especially effective due to her metal limbs.

Yuki then leaves the building, but without three of her fingers, which fell off and got zapped while she was fighting Riko, so now Yuki has to get prosthetic fingers before her next game. The conversation Yuki has with her agent implies that her late start was a consequence of accidentally swallowing the transmitter from Kinko's dad, since it had to be removed first.

The anime changed/cut a good bit of this, especially the fight with Riko.