How events work
After an event ends, the next event begins from scratch. Its conditions will start picking from all instances again.
On the other hand, sub-events (which appear indented) carry on from where its parent event left off. A sub-event will further filter the instances left over by the event that came before it.
Your event is targeting a single Sprite, the one being destroyed, that's why the sub-events can't find any other...
For example, you could add a System action "Pick all", to get all the Number sprites, before choosing one from its ID.