Yes. I think the contrast at the beginning with the woman who is in a hurry to call her granddaughter, oblivious to the sacrifice that's been made to save them both is particularly poignant. During the series, there are so many scenes between Mulder and Scully that take place on the phone, too, as well as scenes where a missed phone call is pivotal. Occasionally phone calls bring us news from faraway, both good and bad, but just as often they're an annoyance.

The phone call at the end could be anyone but since no one knows where Mulder is in hiding, it's most likely a salesperson or someone taking a survey: another example of how life goes on around us in the midst of our personal tragedies.