Place it as the continuous bed under the whole exploration segment, then bring in the x-files theme only for the final reveal, and follow a sudden discovery with the shocking sound effect for contrast.
关于此声音
This is a 15-second ambience clip of hollow room tone, distant fluorescent buzz and faint unsettling noise meant to evoke endless empty yellow halls. It feels quietly tense and isolating, building unease without a sudden scare. It comes from the Backrooms, the internet horror setting spread through creepypasta and liminal space imagery.