Delays in loops - its solved but I am unsure as to why?

So the code is meant to shoot a single cannon ball in a certain direction every 0.5 seconds to create a kind of spinning shot effect. What I cannot fathom out, through a good hour of searching, is why the code works as intended when it is a sub event of the on start of layout. Yet when it is outside the on start of layout it spawns a constant stream of cannon balls in the directions.

I have tried searching the help file for specifics on the start of layout event. But i cannot find anything.

if it's not on start of layout the loop would be triggered once every tick spinshot is true.

You could add the condition trigger once.