Crashing, but behind the spirit simulator

How did he cross over?
Liu Bai floated in the air, staring helplessly at the smooth back of the maid in front of her.
If he remembered correctly, he should have been helping the group of friends taste an excellent Bengsan MMD work just now, what happened after that?
Oh, it looks like the computer has blown up.
Liu Bai felt a phantom pain in his head—even though the ghost doesn't have a head.