[xwdv]

As the author of the original comment, I feel this is the most accurate comprehension. Other comments seem to have taken a more literal read, but that would be incorrect, as clearly the patients are neither dead nor snakes.

I would debate that slither isn’t a negative connotation when used in reference to senses, for instance: electrical impulses slither through the synapses of the human nervous system, allowing us to perceive a reality.