Disruptions in high-current tokamaks can generate mega-ampere beams of runaway electrons (RE) which, upon impact, may damage plasma-facing components. In cases where avoidance strategies fail, alternative approaches are required to protect first-wall components, such as the use of sacrificial limiters or dedicated RE beam mitigation techniques. One promising approach is benign termination via the injection of low-Z material, which promotes recombination of the background plasma. This process leads to plasma termination and has been associated, in several tokamaks, with reduced conversion of magnetic to kinetic energy and an increase in the wetted area, resulting in a significant decrease in both total and localized RE loads on the device. The JET discharge #95135 has previously been simulated and analyzed in detail. Although it appears to represent an atypical case, it is revisited here for further investigation. In this scenario, low-Z injection induces recombination of the background plasma, accompanied by a decrease in resistivity and a corresponding increase in plasma current until termination of the RE beam. During the current ramp-up phase, multiple magnetic island chains are observed in synchrotron images, suggesting the presence of a reversed q-profile. The magnetohydrodynamic (MHD) activity during the ramp-up phase is investigated using the RE fluid model implemented in JOREK. The influence of parameters such as resistivity, RE transport coefficients on the mode structure, rotation and stability are investigated. These results aim to clarify the mechanisms governing the observed MHD activity and their role in the benign termination scenario. Different from the previous studies, where the simulation was started from a violently unstable state, this work will focus on the path from a stable scenario leading up to the final termination.