Plot-holes !! What bugged me about this movie ...
Two things ...
First, I should say that it is agreed that the ending was "idiotic". There is major incongruence between what the husband says and the actual emotional state he is in at the time. Efrem Zimbalist is generally not known for emotional displays (He was good as the main character in the TV series, "The FBI.") But here, he really is almost crying with mixed emotions of guilt, fear, and love for his wife. So, it was rather a strange thing to suddenly revert verbally to the stolid, strict teacher mode. The oddness of what he said there cannot be explained as anything but very bad (unnecessary) piece of dialog.
Second, I would like to ask if anybody wondered how Audrey's character was able to turn the tables on Alan Arkin's character so easily, especially the part where she induces him to toss the box of matches to her. Why should this cool-as-ice killer do that? How does she get hold of the matches? In the air ... or from the floor where they fell? I don't think that anything here makes any sense although things do happen very fast, and the audience is too blinded (no pun intended)by the suspenseful situation here to do any reasoning.
There are probably a few other annoying plot-holes in this movie that other (commenters) may have picked up and commented on in this board.