Lucifer felt that Marvel was no place to stay.
On one side, Chris enthusiastically asked whether he wanted to fight another war between Heaven and Hell. On the other, Mephisto shamelessly pestered him about what was going on between him and Schiller. Why did these people never understand restraint?!
Schiller also felt that he could no longer remain at this magic school.
All the Batmen who had entered the Magic Forest battle had been injured. Now the school infirmary was overflowing again. As the school doctor, he was running himself ragged, bandaging one patient, disinfecting another, and listening to them trade insults.
Although the initial battle had not endangered the Batmen, Lucifer and Mephisto had still held back. But the Batmen were not blind. Seeing the grand spectacle Mephisto had made upon appearing, they naturally turned and ran.
That was the key point. Mephisto had used illusion magic to create magma all over the ground, magic potent enough to fool even Lucifer. Naturally, the Batmen could not see The Truth either. Once they realized they could not outrun the spreading magma, they were hardly going to stupidly keep running across the ground, so they all took to the air.
However, most Batmen were not very good at flying. They had gathered for remedial lessons precisely to practice their flying skills, but Lego Batman had been captured halfway through, and they had never gotten around to practicing. Besides, the terrain in the Magic Forest was far more complicated than a lawn.
So, the group had not actually been injured by Mephisto and the others. After taking off, they had crashed into branches or into one another, falling in clusters and injuring themselves.
Of course, that was only their side of the story. As a professional doctor, Schiller could naturally tell that