The truth must out.
"Grizel," he said impulsively, "you have nothing to be sorry for.

You were quite right.

I did not hurt my foot that night in the Den, but afterwards, when I was alone, before the doctor came.

I wricked it here intentionally in the door.

It sounds incredible; but I set my teeth and did it, Grizel, because you had challenged me to a duel, and I would not give in." As soon as it was out he was proud of himself for having the generosity to confess it.