Path finding is an expensive operation - it takes a while to calculate all of the possible combinations of routes from A to B. That's why the operation is split into parts. 'Find path' only starts the algorithm. It can take several ticks, or even seconds to find a path, so the engine is going to keep running , hitting event 7 over and over again, until 'On path found' is finally called. If you don't turn off event 7 in that time, it keeps starting the path finding again, so it never actually gets to finish finding a path.