Just now, if Test hadn't spoken up and the answer Lucifer gave Luna wasn't the answer she wanted, a big battle would have likely occurred.
And Lucifer didn't want such a battle to happen at all.
If that battle really happened, the possibility of Lucifer winning was quite high because he had fully recovered, plus he had Belial and Test by his side. Meanwhile, Luna was all alone, injured and very tired after healing Lucifer.
But somehow Lucifer still felt that the threat that the platinum-haired girl gave off was very huge. Even if Lucifer's group won, they would still suffer heavy losses.
Although that tense situation had passed, at least for now, Lucifer still couldn't help but feel worried if such an event happened again in the future.
When Luna was uninjured and in her best condition, she might actually win against Lucifer, Belial and Test.