You've provided a good explanation of what's going on here, but one of the great things about Construct is the ability to share your project with a single file.
If you save your project as a single file (.capx) and upload it to a free filehost like dropbox you can share your file here on the forum. (or recreate the problem in a smaller project if you don't want to share your entire game)
So instead of having to imagine everything that happens while reading your post, we can just see exactly what's going on, which makes helping you a lot easier and faster.
That being said, you should also have a look at the "System Expressions" in the manual. A lot of the math you've done can be simplified by using expressions like the distance expression, which returns a distance from one X,Y position to another:
distance(Player.X, Player.Y, Enemy.X, Enemy.Y)