The havenworlders hire a human who docks their ship to the havenworlder's own larger research vessel and uses that for their quarters rather than what the havenworlders have provided. When asked why, the human simply responds "It's better this way." But does not care to elaborate. The reason behind the why becomes clear when a havenworlder goes in to bring a gift to the human that has become such a kind friend and asset, when the havenworlder hears horrific screaming coming from the human's sleeping chamber. Hurrying over, they see the human sitting up, bare in bed, covered in sweat with eyes wide in fear. Once the human has calmed down, they explain to their havenworlder companion about night-terrors, and how some who've seen far too much in their life, can suffer from it. -- Anon Guest
At first, the crew of the Little Blue Bird thought that Human Pri valued their personal space. The alternate speculation was that Pri was one of those Humans who thrived in their own mess, or their own sense of order, and therefore had to keep everyone else segregated from it. They weren't expecting a rare mental disorder.
Somnambulism is not a survival trait in environments that require everyone present to leave the airlocks alone. That said, there are similar disorders that can be worse than disturbing for outside viewers. As Byarin found out when they ventured into the docked Human vessel.
Any unfamiliar ground is automatically liminal, especially when it was quiet. Everything is a shell of something unfamiliar. A shape of something that could be, but currently was not. It was a place where Byarin felt compelled to tread carefully, to mind hir step whilst seeking out Human Pri.