This is Rachel’s tattoo.
“Walk without rhythm” is a reference to Dune by Frank Herbert.
On the desert planet Arrakis any type of rhythmic vibration in the deep desert will attract an immense sandworm which will destroy ie engulf anything it finds (person, spice mine, space ship) in an effort to protect its territory. The desert Fremen have developed a way to walk without any discernible rhythm, only calling the sandworms to them with ‘thumpers’ when they choose.
Dune is my favorite novel, hence the desire for a Dune tattoo, but choosing a quotation was too hard so I referenced the Fremen, who play a central role in the story arc.