Is rescue really used in a trolling way? I get that you can accidentally "rescue" someone to his death. There have been some funny stories about E3N on this forum but that's not trolling at all. The only time I've seen it used in a trolling manner was by myself when me and my FC tried to kill our tanks with rescue. This sounds more like a "I got trolled once in hundreds of fights, fix this ASAP"-situtation. A toggle immunity would be awkward for a healer. How do you give the healer a cue that a person can't be rescued? After the cast failed? Via a buff on the UI? This sounds like a such an unneeded hassle and at that point getting rid of the skill allthogether is the better option.