It's highly probable that this boy, Akira, has a crystal on his person. He may not even be aware that he's carrying it.

You would need to destroy it, but I... also need it, to pinpoint where Ren may be hiding on my end. So I would prefer it to not be destroyed before I can trace it.

Thankfully, as he has not transformed, and is considered a compatible ideal, it will not be fragile, but it will make getting an opportunity to trace it to be difficult.