Low-Z benign termination, achieved by injection of low-Z materials (hydrogen or deuterium), could reduce the damage of a strong runaway electron (RE) beam by evenly dispersing the REs over a large ‘wetted’ area on the wall through large-scale MHD instabilities in the recombined plasma [1]. This method has been investigated experimentally on JET, DIII-D, TCV, and WEST [2-4]. These experiments reveal the roles of the neutral pressure, the RE current amplitude, and the isotope effect in the benignness of the termination. Particularly, the lower and upper limits of the neutral pressure for an ideal RE mitigation scenario have been found [3,4]. To capture the physics behind the experimental results, this work aims to reproduce the expulsion of a plateau RE beam on TCV using the 3D MHD code JOREK [5,6,7]. The MHD model on JOREK can be coupled self-consistently with the neutrals, impurities, and various other physical fields, including a fluid or kinetic description of the REs. In JOREK simulations, the growth of MHD modes, the RE deconfinement, and the plasma dynamics as thermal electrons take over the RE current can be captured much more intuitively than in experimental diagnostics. The modelling of TCV RE termination would contribute to the further understanding of the low-Z injection mitigation and help extrapolate this method to larger tokamaks. [1] Reux C et al, Phys. Rev. Lett. 126, 2021 [2] C. Paz-Soldan et al, Nucl. Fusion 61, 2021 [3] E.M. Hollmann et al, Nucl. Fusion 63, 2023 [4] M Hoppe et al, Plasma Phys. Control. Fusion 67, 2025 [5] M. Hoelzl, et al, Nucl. Fusion 64, 2024 [6] V Bandaru et al, Plasma Phys. Control. Fusion 63, 2021 [7] V. Bandaru et al, Nucl. Fusion 64, 2024