If you die by staying in front of a cleave, you deserve to die. And, again, DPS and healers are already OS by those kinds of attacks...
No, it's being a dick to your healer to save some pitiful damage.
But by taking damage you could have avoided, you reduce the healer's DPS, who should do more than you if you have your tank stance up. And if you don't have the stance up, then you'd take the same damage from that AoE as you do now.
