I tried the "trick" to see if it worked better than the normal way and I do prefer the normal way, but the trick works fine. I've only done Pinnacle on heroic, never on normal, but I assume the same applies. Basically, I had my tank stand where the mobs spawn and the dps/healer a bit away from that. I made sure that consecrate was up once the encounter started. The mobs aggroed me and it took a good bit of healing but I managed to get it done, although tanking, healing and dps'ing all while running another char down to start the event and back was more stressfull than doing the event the normal way, so I'd recommend this procedure only for the achievement.