So, I put an #Ethernet cable under a floor mat, and the friction tore the outer casing apart!
Surprisingly, the inner casings on the conductors inside are still intact, but the destruction of the outer casing has untwisted them. They're just straight wires now.
Also surprisingly, despite the cable now being majorly out of spec, it still carries 100Mbps without incident. Now that's some quality electrical engineering.
Anyway, I got a rubber floor conduit to protect the untwisted pairs.
