Dear Yossi,

The Gemara says she went to the enterance of her house and opened her hair. Perhaps she stayed inside the door and then by the letter of the law open hair is permitted in privacy and others didn't want to enter (although the Mishna Brura 75:14 brings that according to the Zohar it is forbidden).

A prominent Posek suggested that because of her husband's Pikuach Nefesh it was permitted to do the Aveira.