Why did Sa Beining stop Dong Yanzhen from continuing to challenge the impossible?

Because Samaritan made it more difficult, even the judge couldn't see it, so they stopped.

In the first episode of "Challenge Impossible", Xiao Sa increased the difficulty on the basis of the original rules of the project "Footprint Expert", and said with a smile, "Since it is impossible to challenge, we must do one thing at a time", which made Emil Wakin Chau mingle with the participants in the footprint, not only temporarily changing shoes with others, but also changing the position of trying to leave footprints. Dong Qing bluntly said "I can't bear it" on the spot, while Emil Wakin Chau shouted "It's too difficult!" Li Changyu had long been incredulous and said, "If I can guess this, I will worship her as a teacher!" . In the second round of challenges, the difficulty will be upgraded. The challenger needs to find the owner of the only footprint from 30 similar models. After more than an hour of observation, the correct answer has long been ruled out by the challenger. Xiao Sa decisively put forward to terminate the challenge process, and at this time, Li Changyu couldn't sit still on the judges' bench. When the director reconfirmed the rules of the competition, Li Changyu finally couldn't help rushing to the stage and interrupted the recording, feeling wronged for the community policewoman. "We always have to watch it several times in our daily work, and once is not unfair to the challenger." She asked to be given another chance to challenge.