John, forgive me... for what I can't help doing. - Agatha Christie

"I — I don’t regret what I did. I think that you are a kind man, Mr. Poirot, and that possibly you might understand. You see, I’ve been so terribly afraid." “Afraid?” “Yes, it’s difficult for a gentleman to understand, I expect. But you see, I’m not a clever woman at all, and I’ve no training and I’m getting older — and I’m so terrified for the future. I’ve not been able to save anything — how could I with Emily to be cared for? — and as I get older and more incompetent there won’t be any one who wants me. They’ll want somebody young and brisk. I’ve — I’ve known so many people like I am — nobody wants you and you live in a one room and you can’t have a fire or any warmth and not very much to eat and at last you can’t even pay the rent on your room … There are Institutions, of course, but it’s not very easy to get into them unless you have influential friends, and I haven’t. There are a good many others situated like I am — poor companions — untrained useless women with nothing to look forward to but a deadly fear…"

I have no more now to say. I do not know, Hastings, if what I have done is justified or not justified. No — I do not know. I do not believe that a man should take the law into his own hands... But on the other hand, I am the law! As a young man in the Belgian police force I shot down a desperate criminal who sat on a roof and fired at people below. In a state of emergency martial law is proclaimed.

To rush into explanations is always a sign of weakness.