My theory is that Alma was trapped in a time loop too and was seeking a way to break herself out of it (she likely wouldn't know that it results in Loretta being pulled into one as well.) I always felt a solemn desperation to Alma's character. Which is made more apparent by the fact that she's willing to go so far as to steal the Eclipse fragment then conduct an experiment with it that she knows to be dangerous. She wants to break out of the loop that her selves are trapped in, but she unwittingly "expands" the loop which ensnares her daughter as well.

The Eclipse fragment is the key to the mystery about what happens to Alma. And we already know part of the mystery, i.e. the effects the Eclipse fragment has. It's capable of warping time dramatically. It's not until Loretta finds the fragment in the open field, which symbolically has been plowed around the edge in the shape of a giant loop, that Loretta gets pulled into the time loop.