You keep saying "harm" or "injury". There's no such requirement in the statute. It's a reasonable belief the intruder might use any degree of force, no matter how slight, against any occupant of the dwelling. A potential use of force does not equal harm. The word "might" in this statute is very significant. If you can articulate why you thought an intruder might use force against someone in the dwelling that's all that's needed for that element of the statute.
Also, there have been some pretty far-ranging interpretations of this statute by DAs and juries.