Because Nicola's there. She's expecting (probably with good reason) that Patrick will have an extreme emotional reaction to the news of Jon's death, she's expecting Patrick will be extremely loath to be dragged away without knowing why, she's probably expecting that Patrick will guess how bad the news has to be the instant she sees him and she doesn't want all that playing out in front of another child whom Patrick barely knows and she hasn't met at all. This way allows Patrick to have his initial shock reaction in private.