When the room directory changes to show the hotel completely blacked out except for 1408.
"Five. This is five. Ignore the sirens. Even if you leave this room, you can never leave this room..."
That... fucking... phone. And the clock radio.
We've only just begun to live . . .
To say nothing of when it hijacks his video chat with his ex to get her to come up to the room so she'll die too.
For Enslin, in the story, he's so traumatized that he disconnected all the phones in his house and has to sleep with a nightlight. After an experience like that, you can't blame him.
"Even if you leave this room you can never leave this room"
One of the alternate endings on the blu-ray has Mike's editor receiving the manuscript he wrote --though God only knows how he got it-- and reading it. Quotes from the movie begin to play, looping and overlapping each other, including a few from that delightful phone (including one that didn't happen in the movie--"Your daughter is being eaten by wolves on the Connecticut turnpike") as the camera slowly backs away from the editor...through the now-inexplicably empty office. The doors swing shut accompanied by "As I am...", and the movie cuts to black just before "...you will be." -shiver-
In the original short story, the menu sequence.
Also missing from the film (and related): "My brother was killed by wolves on the Connecticut Turnpike..."