Now that the episode is over, one has to ask: will this be the last time we see the telephone in The Walking Dead?
In the comics, Rick Grimes carried that stupid telephone around in a backpack for a long while. Eventually it went away, but only after he was discovered and mocked by Carl. By that point, the story had run long enough that most readers were pretty ready to mock Rick for his ongoing series of conversations with his dead wife, as well.
And, frankly, when the phone rang last week, at least this fan was extremely skeptical of whether that fairly absurd story from the comics could be successfully adapted. If this week is all we see of it, it was pretty well done and accomplished its apparent goal -- allowing Rick to take guidance from "Lori" to get himself back on track -- better than the comics managed. If this isn't a one-off, it could be an even riskier proposition to bring the concept back, since it's not just Lori but a whole group of lost survivors that he spoke with, which means it's virtually impossible for him not to realize how crazy it is to carry on answering the phone after this.
It also seems less likely for the "phone story" to continue for a practical reason: here, unlike in the comics, the telephone is in the prison. When he needed to leave the building the phone was in before, he was able to grab it before they ran. In the prison, it seems unlikely there will be opportunity to do that; there certainly wasn't in the comics.