['Significance'... Mikami wonders how to put this. There's two things. L's attempt to contact him and the fact that Light - or rather this strange version of him- had been following L that week. It's not like there had been anything of importance in that incident, except for the amazingly immature interactions of L and the fake Light that had occurred. He could as well save that for later. The first part was more important]
I was contacted by the detective. He wanted to cooperate with me for this place's justice system. [The way Mikami says it though makes clear, that he sincerely doubts that it was the real motive. It had been a private message to him only. Why only to him, when it concerned all the other detectives as well? Mikami didn't feel good about the fact that somehow L had gotten wary of him, but regardless, Light needed to know]
no subject
The first part was more important]
I was contacted by the detective. He wanted to cooperate with me for this place's justice system.
[The way Mikami says it though makes clear, that he sincerely doubts that it was the real motive. It had been a private message to him only. Why only to him, when it concerned all the other detectives as well?
Mikami didn't feel good about the fact that somehow L had gotten wary of him, but regardless, Light needed to know]