Savage mode, old Coil T13 and so on... That skill saved life, but as not main class SMN you may never experience such situations because those situations are rare and should not happen... still you can change gear to less lifepoints when SMN and HEALER were working in team, Physik was doing just the edge for surviving some Bossattacks you would need 2 healers (with teamwork you can soloheal hard content)