Well, of course Harriet's happy when the loop breaks. The whole reason she was on Blackreef was to actualize her inner self blah blah and reach a place with no suffering called the Great Beyond. She went to bed one night in the old world and woke up in an entirely new one. It worked! (Let's not burst her bubble just yet).
Many of the Eternalists go down without much of a fight, can easily be outsmarted and generally do an abysmal job trying to stop Colt. Their artificial stupidity could be a case of Story And Gameplay Integration. Colt is a military veteran and the head of AEON security, while most of the Eternalists are untrained hedonists who are likely high or drunk when they face Colt (many can be seen guzzling alcohol while on patrol) and would stand no chance against someone who actually knows how to fight.
In Harriet's diary entry should her ritual be successful, in which she speaks about having become the arbiter of life and death after dropping Amador into the gas, she specifically mentions it happening in a hangar full of airplane carcasses like the one that killed her parents. In real life, lots of people who die in plane accidents do so thanks to things like inhaling smoke or toxic fumes. Might little Harriet have seen her parents or other passengers surviving the crash but suffocating to death before her eyes? Could this be the reason she chose this method of sacrificing Amador?
