You're misreading it. They don't have to meet up or speak to be within one another's presence, even if that presence is between ships, or maybe she's somewhere on the Infinity itself but due to the whole Del Rio fiasco they can't get to her and gotta get off. Something truly preventing them from reaching Halsey when she's so close. In 343's reality, she was never really an option and she's hardly even a plot device because she's never there and they never intended her to even be a possibility (yet they still opened the game with her and made Halsey the tone of the game).