In Act 3, Frank argues with Vivie about her mother, expressing his disgust for Mrs. Warren's profession and rebuking any semblance of closeness between her and Vivie. Frank clearly abhors Mrs. Warren, using hyperbole to emphasize just how much:
FRANK. Because she's an old wretch, Viv. If you ever put your arm around her waist in my presence again, I'll shoot myself there and then as a protest against an exhibition which revolts me.
Despite his own attraction to her and her daughter, Frank despises what Mrs. Warren stands for, seeking to discard her and distance himself from her ill reputation. Frank uses extremes of language for this, insinuating rather dramatically that he would prefer death to Mrs. Warren's proximity.
Notably, these extremes of anger and abhorrence may not stem from Mrs. Warren alone, but from a disgust and shame Frank holds towards himself. He likely inherited a great deal of religious, moral guilt—both from society and from his clergyman father. When Frank looks at Mrs. Warren and desires her, or when he looks at Vivie and plans for a future with her, he cannot help but look inward. He questions his own "morality" because of his proximity to the two women. Frank lashes out at them not because they are at fault, but because they remind him of his perceived failings.
In the following passage from the end of Act 4, Mrs. Warren emphasizes the difference between herself and her sister, Liz. The two women, Mrs. Warren argues, would be ill-suited to each other's respective environments. She utilizes hyperbole to demonstrate how she would be out of place in Liz's sleepy "cathedral town" in the countryside:
MRS WARREN. Oh, it's all very easy for Liz: she likes good society, and has the air of being a
lady. Imagine me in a cathedral town! Why, the very rooks in the trees would find me out even if
I could stand the dulness of it.
Mrs. Warren attempts to emphasize to her daughter how ill-suited she is to provincial, pious life. She uses hyperbole to stress just how out of place she would be in such a place, stating that even the "rooks" (or crows/ravens) in a small "cathedral town" would eventually find out about her past. While birds would in reality care very little for Mrs. Warren's sexual history, Shaw uses this overstatement to draw lines of contrast between Mrs. Warren and the rest of the world. Like those around her, Mrs. Warren believes her "true nature" incapable of change; or, rather, believes that she should not have to change to fit social conventions of decency and propriety. This staunchness of Mrs. Warren's true nature, discoverable even to the crows, becomes a source of much intergenerational conflict between herself and Vivie.