Don’t get why Yoshihiro couldn’t remain in call with his son

I am referring to the moment when Josuke realizes Kira knows his location cause his dad is in Hayato’s pocket, but at the right moment he does the lighter thing and talks about it Yoshihiro doesn’t seem to be on the phone with Kira and that could be useful. Any explanation? I have watched it completely many time ago just rewatched the clip some minutes ago