As Gabriel runs his fingers over that spot, he'll feel that it's not as smooth and regular as the rest of the spinal cord had been; some half-healed chipping, some stray injury or projectile sustained over the course of its life that never quite repaired correctly has left the surface ragged and a little thinner.

It's an old injury, most likely. A scar, a token of some other target's violent regard. Now it serves no other purpose than a reminder the machine can't even see - and also to make it make interesting noises, apparently.

Which it proceeds to. There's another spike of stimulation, another burst of vented excess heat to go with it, and it shifts against him, pressing its back against his hand with a slight shiver. It doesn't need words to convey its desire there.