If the fire is seen has uncontrolled, uncontrollable and can light up the ammo dump anytime... you abandon ship and left just minimal staff to try to maintain pump and fire system if they are operable. That staff is probably the 27 missing... not sure if having 300 missing would have been better.
given the fact that the fire did not appear to have lit up the ammunition store at all even after the fire appeared to have kept burning intensely for quite sometime after the ship has been abandoned, and the ship nonetheless took a long time to sink, it does appear damage control did not accurately appraise the situation, and may have panicked, and the ship was abandoned too precipitously.
It seems to me the only explanation that does not impugn the crew’s performance is the Russian navy did not put a very high value on the ship and did not believe the ship to be worth further casualties to save.
One question I have arising from photos of the damaged ship is what other russian warship was in company with the Moskva? When the salvage tugs in the picture were standing by the Moskva, what is providing the floatilla with protection against further ukrainian missiles? If there is no other warships providing defensive cover, that implies the russian were quite willing to accept further casualties to help the moskva. this in turn implies the moskva was not abandoned as a matter of casualty aversion.