On lv65 the zumi healing skill is at 2.2k =D
Wow that's some OP heal amount if the value you said is for the per second one.
So I just tested Strategic Retreat (in Trial) and it doesn't remove me from combat. As long as I healed party members before I used Strategic Retreat, their combat will keep me in combat. I'm not sure what will happen in Territory War if it has a different mechanic.
Duels can get out of combat but you need the person to stop attacking, which can sometimes get out of combat by itself. PVP is pointless to try and revive if someone dies since people tend to continually attack the healer.
The heal value is nice but can be easily lowered back in TW, PVP, and Duels. In dungeons, it's nice to help keep yourself alive but I haven't really used it for those situations yet. :x