I'm trying to learn Slayer's War Ensemble and just not sure what I'm doing for (Rhy. Fig. 1) in this tab: http://tabs.ultimate-guitar.com/s/slayer/war_ensemble_tab.htm

My left hand does fine but with picking I'm not sure if it should be all downpicks or alternate picking. Downpicks seems more natural to me without getting too tired or sore, alternate picking confuses me. What way should I be doing it though?
downpicking seems like the logical choice for that section i would say. If you don't get tired or sore in your hand by doing it, then i see no reason not to play it by downpicking