I”ve been wondering the same thing myself. They can’t transport via planes because the airports are under fire. Trucks are slow and use a lot of precious fuel. Maybe use the refugee trains returning from the borders? It will be interesting to see how they do it.
Putin thought Ukraine would just roll over like they did when Russia seized Crimea. Now people are wondering about his sanity.
Unlike a lot of professionals, I’m not discounting Putin’s threat of nuclear war. I think that two years of pandemic isolation has skewed his thinking. At this point, I wouldn’t be surprised if he did launch a few nukes.