The rationale behind my belief that in-person is best is for them to see your calm resolve. You look them straight in the eye, and calmly, firmly yet lovingly deliver your script (practiced dozens of times ahead of time, btw, lol). You want them to see (or at least hear, if you have to do this by phone) your calm resolve and strength.
Starsky
Hmm... Something to consider... Maybe waiting until she's down to grab her stuff is a good decision...