Luka is still in the parking lot of the Bamborough Cafe, typing away into the group text on his phone. He's distracted enough by the conversation that he doesn't pick up on or notice the pull of Seven fading, or perhaps completely disappearing, when they retreat into the hole and abscond from their encounter with Matilda.

It's only when Luka pulls himself away from his phone, intending to catch Garrot and Olivia up on what he'd learned that he suddenly feels Seven's presence re-emerge all at once.