[Formendacil]

If Eowyn is selfish in abandoning her responsibility, and wishing to go off to war and glory, is Theoden not equally guilty? After all, as both an old man and the king of Rohan, it would be more natural for him to remain at home, instead of Erkenbrand, and send the younger marshals out to command the army. Instead, he wants one last gasp at glory.

Now, I admit that Theoden had some more altruistic reasons than that- such as the morale it gives his men, but to Eowyn it might appear as such.

Perhaps Eowyn is following her uncle's example: first she does her duty, as does he, then she goes chasing after glory, as does he.