Might not be helpful to AensleigheR, but maybe will be to someone else.
Are you talking about the stages? Well yes I have, I have set the screen bound from 1000 to 10,000 but still my helper gets stuck when the move misses.You want to put a ScreenBound state controller in your helper's state, which will allow it to actually go off screen. The simplest example of such SCTRL would look like this:
[State whatever]Then you can use DestroySelf on the helper when it's well off the screen. You should know its approximate size in pixels and the direction you have it move in (most likely, forward). Say, it's 100 pixels wide and moves forward. In this case, when its FrontEdgeDist reaches -50, it's entirely off the screen: -EdgeDist triggers take the difference between your character's X axis and the corresponding edge rather than your character's edge and the stage edge. Multiply this by 1.5 just to make sure and you have this:
type = ScreenBound
trigger1 = 1; active always while the helper is in this state
value = 0; allow going off screen
[State whatever]If your helper is moving backwards instead of forward, you do the same, but use BackEdgeDist instead of FrontEdgeDist. -Dist triggers are more reliable than -BodyDist ones in case you have to go beyond the screen boundaries because they don't depend on the width and height of your character.
type = DestroySelf
triggerall = ishelper; it's good practice to perform this check.
; If you accidentally put this SCTRL into a non-helper state or
; if your helper shares states with the character themself, you
; won't get the "DestroySelf called for non-helper" message.
trigger1 = frontedgedist < -75; adjust as necessary