At the same time, it reads as though you didn't know the last part of the play if you didn't reference it properly. If you legitimately reject it and provide evidence, then it's convincing, but if you simply ignore it, it shows a lack of knowledge.
The weaker student will say: No, this question is wrong, here is the stuff I remembered.
The stronger student will tackle the ending scenes, or work to disprove their importance.
I suppose the point I'm making is you had to make at least some reference (quotes!) to Act 5, regardless of your thesis.