How to see what happens after click, line by line?

After using my custom grid script I get a good result with different types of choosers except one. That one breaking all my system, I get a result as it was 1650 units size. But in the editor, and in the script, and in the formula it is 1100! I want try to see what happens line by line, after a mouse click. When game on a pause - it didn't get inputs, when not - after a one frame code already executed. How I can do this?