They tend to kick when they feel threatened.
Answer with Explanation:
The play increases tension when Mrs. Stevenson received a telegram from her husband. The telegram informed her that her husband won't go home that evening because he was on a business trip to Boston. Mrs. Stevenson then felt breathless and stated "Oh,no-." This clearly shows that her husband won't be able to protect her that night, especially that she was sick and she was sensing something bad about that evening. When she tried to call her husband's office again, she cried because no one was answering it. This then increases the tension further more because she was becoming hopeless.
