the passage on minion res states this:
Summons have an innate resistance bonus which increases at 15% per soft point in that summon (caps at 75% and is hidden). They suffer the resistance penalties of Nightmare and Hell, requiring around 50% minion resistance and a full 75% (total res caps at 50% in Hell) from different sources (usually from items) in both difficulties respectively. You cannot overcap summon resistances.
Does this mean there is really no way to keep summons alive in Lab 9 and 10? Cause mobs have 100% ele pierce in there