It's got nothing to do with the missiles, it's about trying to keep out the Russian soldiers attempting to get inside, they matter rather more than the missiles.
That depends on the number of missile and the goal. If the goal is destruction, missiles alone will work if enough of them are used. If enough of the city is destroyed and enough of the inhabitants are killed, Russian soldiers can get inside afterwards.
As Tacitus said of the destruction of Carthage - they create desolation and call it peace.