"Sorry, folks. I understand the frustration (both as a performer and an audience member), but I wouldn't go so far as to say that it was handled professionally. Stopping the show because you're annoyed is just as distracting, if not more so."
The beautiful moment was already ruined by the incredibly inconsiderate, dumb moron who allowed their phone to ring...what 5 times? Oh my God. The person should have been thrown out of the show, just like if anyone's cell phone goes off. It's posted in the lobby, it's in your Playbill AND it's announced before the show. There is zero excuse, ever, for having your cell phone on in the theater. They need people to check their cell phones at the door before entering (some movie theaters do this now) but I guess it's not feasible considering there is no desk to check in your phones at most Broadway houses.
If you are an inconsiderate person with no respect for other patrons, the cast, crew and every one else involved in theater, do not attend the theater.