Why is Hisa holding a can to Kana's face?

Because she can?

Was that a pun?

Normal cliche situation, she just came back with the drinks and interrupted Kana y scaring her with a cold can to the face.

Now, if any creative mind can come up with a punchline, it won't sound so normal.

I say it's her subtle way of challenging Kana. >8DDD They're like the warriors for Mihoko's heart....or something.... *hyperactive imagination* XD XD XD

I doubt Hisa has any idea Mihoko has a crush on her. The same could be said regarding Mihoko and Kana, but that may be because everyone on her team has affection for her.

Considering this is Hisa we are talking 'bout, she may be using a tactic she saw on TV to help Kana admit her love for Mihoko: using something cold to make her relax or something, y'know?

If that is true, just being there ruins it.

I think from the surprise, Hisa just happened by.