The victor of an assault is calculated as for a normal close combat, however combat result points can only be scored by inflicting wounds (including overkill wounds scored in a challenge, if there are any). Standards, ranks, flank and rear bonuses, and so on do not apply (the last two primarily because a unit in a building cannot really be said to have a flank or rear). a musician will still win a drawn combat, however. Otherwise, the close combat result is based purely on casualties.