Sakura Ayame told them everything.
Although she worked in that industry, she was naive and inexperienced in dealing with people, still a university student. Sakura Ayame was unaware that Morimoto Chiyoda's actions could have been countered with a charge of intimidation; she was so frightened that she spilled everything.
Of course, the information Sakura Ayame provided consisted of only a few sentences, yet it allowed Morimoto Chiyoda to grasp several key points.
First, the stun gun that instantly disabled Sakura Ayame was useless against Dio.
Second, Dio had knocked down three people from a distance.
This wasn't because Sakura Ayame saw it herself, but because Morimoto Chiyoda learned it from the conversation Sakura Ayame recounted.
"Senior?"
"AH!"
"What—what happened to all of you? Was it you, you jerk?"
This brief exchange contained a significant amount of information.
