Sukuna broke free, hence Rika’s arms no longer holding him despite the fact that they previously were, same for Yuji.
Sukuna can fire slashes without movement, proven against Kusakabe, it isn’t unlikely he cut them off, then aimed at Yuta.
He didn’t move back, the Cleave pushed him back. Nor would it have killed him, hence him saying he doesn’t fear the slashes anymore. The Sukuna in 251 has lost considerable output and control, as stated by himself, hence Yuta just running through Dismantles.
The entire narrative of Yuta bringing him into his domain was to force him into a scenario where he literally couldn’t use the WCS, and force him to be handicapped, with the narrator outright stating that Sukuna relied on a desperate gamble to get it off.