It was almost as if there was an invisible wall.

[Vladv1]

"A bar-restaurant open each night until 2 a.m., the Wife Swapper became Bon’s ‘office’ throughout July and August. Making himself at home, he
quickly hooked up with another teenage girlfriend-cum-fan: 16-year-old Helen Carter, a Bondi beach babe who’d been a regular pub-goer since her
early teens, and would later form the post-punk outfit Do-Re-Mi (who hit the Oz charts in 1985 with the single ‘Man Overboard’). Sharing Bon’s bed
at the Squire, though, meant sharing the room with Phil and Mark too. ‘Bon had the double bed because he was the oldest,’ she would tell Clinton
Walker. ‘It was almost as if there was an invisible wall". The Bon Helen recalled was ‘meticulous’ in his dress sense: basic jeans and T-shirt uniform but always ‘perfectly laundered’; the sort of guy who washed his hair every day and styled it with a hairdryer".
Mick Wall, "Hell Ain't A Bad Place To Be".

What does the phrase in bold mean here? To me it seems out of context.

 

[Flask]

Even though sharing Bon's bed meant sharing the room with Phil and Mark, it was as if there were a wall which could not be seen but which provided Helen and Bon with privacy.