We give a short proof of the discontinuity of phase transition for the random-cluster model on the square lattice with parameter q>4. This result was recently shown by Duminil-Copin, Gagnebin, Harel, Manolescu and Tassion via the so-called Bethe ansatz for the six-vertex model. Our proof also exploits the connection to the six-vertex model, but does not rely on the Bethe ansatz. Our argument is soft and only uses very basic properties of the random-cluster model. Joint work with Gourab Ray.