Scratch

I've got the script for pointing towards a set of co-ordinates. But something strange is happening:

when  clicked
set 
delta x ▼
 to 
item 
1 ▼
 of 
xlocations ▼
 - 
x position
set 
delta y ▼
 to 
item 
1 ▼
 of 
ylocations ▼
 - 
y position
if 
delta y
 = 
0
if 
delta x
 = 
0
set 
ideal direction ▼
 to 
-90
else
set 
ideal direction ▼
 to 
90
else
if 
delta y
 < 
0
set 
ideal direction ▼
 to 
180 + ([atan v] of ((delta x) / (delta y)))
else
set 
ideal direction ▼
 to 
atan ▼
 of 
delta x
 / 
delta y

I have a turning script after that.
When the target location is -100 -100 the ideal direction is 225, an unreachable target so it just keeps rotating