"You don't have anything to be sorry about." Chizuru didn't do anything wrong. She's just trying to help... though he can feel the worry threatening to consume him anyway. It's not like they can do much of anything while Zero's still recovering, but...

His hands shake slightly, but he tries to stay steady for her sake. He can't... he just can't sit around and do nothing... "I wish I could... just go back when I want to. It's not like that here, though. I can't just step through a portal and go somewhere else." As much as he'd like to... "I just don't want more people to get hurt. So many people are suffering there... it's a world where nothing can die."

As nice as that might sound to some people, it's... horrible. Coming back again and again, with no rest... "There's too many people who have given up hope. ... I just want to help. But I can't from here." He grimaces, his fangs a bit extended. "I can't... and it's frustrating as all hells."