So the only solution is to find an alternative way to enter sneaking.
But there doesn't seem to be any. CharacterApplyStatus(__Me,SNEAKING,-1) consumes 5 AP in combat. And Skills don't seem to accept Sneaking as Skill Property.
I made the experience that manipulating statuses via character scripts can cause a game crash, at least it happened when I tried to remove a status immediately after it was applied. Means that care has to be taken with status application and removal in character scripts.
Yeah, I always use a short timer in those cases.