She did not schedule any time alone with Chism. He had already planned to kill her. Chism brought a “murder kit” to scholl with him. She was never intentionally alone with Chism. Chism followed her into the 2nd floor women’s restroom and attacked her.
I meant, it sounds like the facility was closed and no one else there.
In the sense that she asked him to stay after class for a test prep/tutoring session is scheduling time alone with him. If there were a second adult around, with protocols, like both are in the room, if one leaves the other ensures that any students remain in the room, then it would be safer... maybe.