It would seem to me that the purpose of this station would be as a mining colony. As such, the 'ore' would be collected in orbit around the asteroid, until sufficient quantities had been accumulated to make transport economical. The asteroid has some gravity, so these 'booms' of ore would have some orbital velocity. I would posit that a resupply ship was in orbit at the same time as a tug was maneuvering to capture and transport the mineral boom. The two catastrophically collide, due to a solar flare damaging their navigation systems. The tug, mineral boom, and resupply ship lose orbit and crash into the station. Maybe add in a last-minute flurry of activity of local tugs taking ore up to the boom, which are critically damaged and add to the catastrophe. This damages the external shielding of the station, allowing the radiation from the solar flare to penetrate deeply into the station.
In would be an unusual coincidence of solar flares, the base being oriented towards the sun due to the rotation of the asteroid, the presence of the loaded ore boom, the tug and the resupply ship. It would be a critical period in navigation such that the navigation systems of the ships could not be shut down to harden them from the solar flares.
Lots of drama, excitement, and converging plot lines.
Take out the docking ports on the station, and critically damage the electrical systems on the lower levels from the effects of the solar flares. The electrical infrastructure would probably not be hardened below the top levels, due to economic constraints, with good reason. Once the top level goes, the lower levels would not be viable, hardened or not. Maybe even throw in a loss of atmosphere from the habitat that can no longer be resupplied. The hydroponics would be on the first levels, to make use of the solar energy. Certainly, most of the solar panels would be taken out by the falling ore.
Perhaps the ore on the asteroid was almost depleted anyway, so there is no longer a financial incentive to bring it back into production. Sufficient resources are left to keep a maintenance level of staff healthy, but no more.
Not sure how much of this fits in with your plot line, but it might be useful for other scenarios.