User blog comment:The Milkman/Indoctrination Theorists Say the Darndest Things/@comment-4941068-20121023181702/@comment-4237253-20121023210458

Usually, you can spot a deus ex machina if it's sole purpose in the plot is to resolve the conflict. A more relevant example would be the Crucible itself, introduced early on as a means of ending the Organics vs. Reapers conflict.