We see a point of view from the road, through binoculars. Eve's headphones are visibly leading to something she is holding - something not the phone she just dropped.
Computer voice Tell the cleaner to show her music player.
Eve takes the kidnapper's phone out of its case, made awkward by the headphones.
At the same time, we see on Eve's phone video that Carol's phone is pointed towards the door of the room Eve is inside.
Computer voice Drop it.
Eve holds the phone case, concealing that it's empty, and drops it.
We see on Eve's phone that Walter is walking towards the guest bedroom door.
Eve leans against the wall adjacent to the window in relief, closed eyes, that she got away with that. Not yet noticing Walter's approach.
Computer Voice Good. Await further instructions.
The computer voice (no longer plugged into an headphone jack) echoes through the room, and we hear in response, both on the phone and through the door...
Carol (MFL) That was definitely something.