I don't know what impelled me, but I was nettled, and I said
foolishly and not in the best of taste:

"Yet you seem to be invariably charming to Dr. Bauerstein!"

Instantly I regretted my words. Her face stiffened. I had the
impression of a steel curtain coming down and blotting out the
real woman. Without a word, she turned and went swiftly up the
stairs, whilst I stood like an idiot gaping after her.

I was recalled to other matters by a frightful row going on
below. I could hear Poirot shouting and expounding. I was vexed
to think that my diplomacy had been in vain. The little man
appeared to be taking the whole house into his confidence, a
proceeding of which I, for one, doubted the wisdom. Once again I
could not help regretting that my friend was so prone to lose his
head in moments of excitement. I stepped briskly down the
stairs. The sight of me calmed Poirot almost immediately. I
drew him aside.

"My dear fellow," I said, "is this wise? Surely you don't want
the whole house to know of this occurrence? You are actually
playing into the criminal's hands."

"You think so, Hastings?"

"I am sure of it."

"Well, well, my friend, I will be guided by you."