Honestly I'm all for a toggle that allows you to be unaffected by rescue but on the flip side have you tried actually putting on your big kid pants and actually doing large pulls? A level 80 Dark Knight afraid of doing wall to walls? Seriously? Heck, even in low level ARR dungeons there's no reason to do single pulls.

Healers can't rescue you into more mobs if you're already ahead of them.

You're a high level tank. Please play like one.