When questioned about his "missus" he replies "what about my missus" - preserving his independence was the following line. This only goes to show that Stanley was a male chauvinist totally selfish and felt that women ought not be independent but to be domineered by men! Tom on the other hand was a seventeen year old, obviously he was living his adolescence unfortunately he had two narrow-minded chauvinistic men to be his guide!.
In the middle of the passage, we note that the men take turns to go have a peek at the woman whilst working and they report to one another of the progress that she's made. When it came to Tom's turn he did not report the truth of what he saw. He lied to them apparently because "he wanted to keep what he had seen to himself: he had actually caught her in the act of rolling down the little red pants over her hips, till they were no more than a small triangle. She was on her back, fully visible, glistening with oil". Tom, I believe was under the impression "hey, I saw it all! This sight was especially for me, I mean something to her, that's why I was the one to see her naked". He not only had intruded the woman's privacy by watching her sunbathing but by assuming that he meant something to her in his mind.
Towards the end of this paragraph, again "the woman on the roof is sunbathing, face down and arms spread out, donning only a little red pants. She had turned brown, for the day before she was scarlet and white woman. Stanley let out a whistle. She lifted her head startled as if she was asleep and then looked straight at him. The sun was in her eyes, she blinked and stared, then she dropped her head again". At this gesture of indifference, the three men let out whistles and yells and they were all angry including Harry", the older man. Lessing reveals here that this woman couldn't care less of these men and their attitude towards her. Her boldness in ignoring their catcalls, and not being intimidated seemed to irritate them all the more.
