Why do you think Eveline let go of the opportunity to escape?

Eveline let go of the opportunity because she was strucked with the memory of her mother and siblings. Also, she felt a sense of responsibility and was burdened by the promise she made to her mother that she won’t let her house to break and she will hold all the members together as long as she could. That’s why she did not elope with Frank feeling a sense of responsibility towards her mother and family.