After looking things over Karu will be using her second wind and using an action point to make a reaping strike against #3 (-2 from violating the mark from #2). I intend to maintain the mark on #3.
Shifting away from the spark would loose Tanglar his flanking and leave #2 free to attack so I guess I get to see what exploding shards feel like.
As a side note, can you ever use healing skill on yourself?
* Reaping Strike against #3 *
* Reaping strike dmg, 4 dmg on a miss, brutal 2, high crit weapon *