You know it’s going to pop when the part on top of the middle square that displays the amount won, when that top part stays blank. If you get rockets and it’s blank, that means at least one of those 🧨 will pop. If you get a rocket and it says 50 lines, that means the games over but blank means game is still on going. I noticed this when I first played the game. Like any video game ever created, it will always let you know when the game ( your turn) is over. So always pay attention to the machines and you can sometimes tell when bonuses are over.

Better luck next time!