The Bible doesn’t use modern terminology. Moses and the other biblical authors didn’t use the terminology of modern physics, astronomy, geology, chemistry, psychology, and other sciences, so we can’t expect them to describe natural phenomena in current, scientific language. Therefore, we shouldn’t be surprised that the Bible doesn’t refer to “attempting access to the subconscious.”
Modern psychology may be wrong, but its present day model implies that mediumship involves the subconscious mind. This modern insight into mediumship/channeling is a secular confirmation of warnings in Scripture against mediumship, just as the “big bang” theory developed by astronomers and physicists is a secular confirmation of the fact of creation. Genesis doesn’t describe creation in terms of modern physics, but its description is remarkably detailed, accurate, and understandable to modern people. In the same way, even though the biblical authors didn’t use modern “scientific” language or concepts, they were accurate in their fear of mediumship and justified in their condemnation of it.