Hi
You could probably use bounce if you want.
The one that's meant to flee lets call it"a".
The one that makes it flee lets call it"b".
Umm you probably have to input-
The behavior for "a"--Line of sight
The event-
On object-"a"-Line of sight x pixels from "b"
The action-
"a"Set angle away from "b"(if that is possible).
I hope I've helped,
SHIRATSUYU