Group quest fun - forgetting my spells

Last night I and some guildies did Turning Point, the quest where you go to bash a 5 man outdoor elite. So for fun I got to heal the paladin tanking. It was ok; I kept earth shield up on him and managed to keep his health topped up. I even managed to heal the hunter in the party when he took damage.

But the mad mage, that was a different story. Apparently Socrethar does a spell reflection, so the mage's health goes from full to 1/2 and then down to 10% in like 3 seconds. I desperately cancel my current heal, target him and try to cast a healing wave, but he's dead. Doh.

What could I have done differently? Not forget Nature's Swiftness for a start, and try a Lesser Healing Wave instead. Oops. With a NS + HW I could have probably got him back to full, although he may have then just killed himself again with another fireball... Suffice to say I've put NS onto my healing bar and am considering sticking the emergency NS healing macro on there instead, as posted here.