Kraprivnik - IL-76 Shot Down - Steadfast Defender 24

Stanislav Kraprivnik on Ukraine shooting down the Russian heavy cargo plane, IL-76, carrying 65 Ukrainian POWs that was shot down by Kiev. Obvious Ukraine did it, but why?
Russia's patience in not responding to these constant provocations that could lead to a nuclear WWIII.
Operation Steadfast Defender 24, the largest war games on Russia's borders since the end of the Cold War.
What is Russia to do?