Russia never cut off gas supplies to Ukraine in the middle of winter...And Ukraine soldiers defected by the thousands when the battle for Crimea was raging.
They did so in 1992, 1994, and 2005. The temperature was -30 in 2005. Russia wanted Ukraine to pay for the gas they received but didn't want to pay transit fees for the gas transshipped through Ukraine. Everything really belongs to Russia after all, right? It was a blackmail attempt to get Ukraine to hand over ownership of the pipeline. Putin did the same thing with success to Belarus.