What Happens if a Nuclear Sub Submarine Sinks?

I am glad India is now staying far away from Ukraine. It's a hostile nation. We should stay away from it and well, good luck to them for what's coming. The Ukrainian government cannot help. And the financial portal zero hedge governments, we wonder if that was rather unhelpful attitude has anything to do with India not imposing sanctions on Pakistan. Like I said, the Ukrainians have been supplying tanks to Pakistan and all that. There are way more aircraft in the ocean than there are submarines in the air. So submarines are safer than planes. Now, what happens when a nuclear sub if a nuclear submarine sinks? Well, if it sinks, it's dangerous. Are there any sunk