>>5951852>>5952101>>5952102Another really weird thing to try, but bear with me: there is that apocryphal Egyptian (?) tale of how before modern medicine, some ancient physician / apothecary was trying to locate a good site for a hospital or something. So the method he devised (before they possessed any understanding of germs or bacteria or microorganisms) was to visit the local butcher, procure slabs of meat and then hang these slabs of meat across the entire city on hooks. The ancient physician then observed the meat and the speed of decay over several days; after a week or so, he visited all the locations and chose the site where the meat from the butcher had not gone rotten or decomposed the least / attracted the least flies etc as the best site for the hospital.
So in a similar manner investigating this strange interdimensional reality defying tunnel, maybe try and find some food or something easily perishable like milk, yoghurt etc and leave it in a dish inside the tunnel space. If the food decomposes it means there are microorganisms bacteria etc surviving in the space, it proves that it must be biologically survivable to at least some basic forms of life etc as opposed to an inert or hostile alien environment
>it is like putting out an enticing food offering to tempt out any demonic entities within, yay 