That is a strategy. The strategy is to live as long as they can through heals and damage the opponent from poison/iginite/etc. I've read somewhere in the forums that this is countered by heavy nukes. I believe the ninjas involved were fire main, onoki, pain shurado and konan.

I just beat this triple healer team in arena last night facing a 70k Six Paths Sennin in Training Battle (I know my opponent was 70k+ coz he/she was wearing the samurai outfit). I used the team I heard that I posted above. Konan, Shurado, Fire main, Onoki. Hokage Tsunade was already dead after round 1 from Shurado mystery+ignite. Round 3 killed Water main. Round 6 Roshi and Sailor Sakura died at the same time. Or maybe I was just lucky that time coz Shurado mystery crit Hokage Tsunade at round 1 + Fire main chase hit Water main and Sailor Sakura igniting them + Sailor Sakura was also immobilized by Fire main's mystery so no AOE damage on my team.

Yes that is true but the point of my post is that, Immortal teams aren't really immortal.