you have placed the pan_create code inside a while loop. This means you will be creating panels constantly and this is one hell of a memory hog.

Place...

panel = pan_create("digits (0, -80, 2, standard_font, 1, my.enemy_pan);flags=visible | overlay;",1);
my.enemy_pan = ang(my.pan);
digits_set(panel,1,my.enemy_pan);

...just before the while loop instead of inside it.