I don't mind that she went into the cage to help Yanis--confronted with his suffering, rushing in to help him was the right thing for Cosima. But I do mind that she rushed off to "stop" Westmorland without any sort of plan for how to do so. Especially given that she knew Delphine was already working on a plan that would be endangered by Cosima's rash action.

Cosima has a great big heart and that is wonderful. But she has a big brain as well, and sometimes I'd like to see her make more use of it!