It was impossible for the little Roaring Flame Tigers to survive for tens of thousands, hundreds of thousands, or maybe even millions of years... No, maybe even longer, who knows.
If the Kang Kingdom really had a soul evolver capable of drawing such advanced runes such as runes capable of stopping the passage of time within a certain area, then Kang Guiying would not have needed to force a part of his soul into a Fourth Order Soul Stone just to leave a thread of his consciousness behind in order to carry out his final will. The king could have simply locked himself inside a room where the flow of time had stopped thanks to the runes and waited for his trusted subordinates to find some divine medicine capable of healing his critical injuries.