[Well, Subaru himself could certainly handle the monsters, too... but he isn't in any mood to want to fight them. So he simply shakes his head, knowing what Sei is referring to.]
He's... not here. So it's alright.
[Except it isn't. He hasn't spoken with his twin ever since their confrontation a few days ago, and hasn't sensed him around on the main island, either... so it must mean Kamui doesn't want to see either of them. And that's kind of incredibly painful to think of, especially as he knows it's probably all his fault.]