Why does Roger wash his face instead of running in "Thank You Ma'am"?

In Langston Hughes' short story "Thank You M'am," a teen boy named Roger attempts to steal the purse of a large lady named Mrs. Jones. Roger claims that he is stealing the purse because he would like to buy some "blue suede shoes." Like most teens, Roger is obviously very much aware of how he appears to the world and wearing such trendy shoes would make him seem worldly and important rather than poor and insignificant. His unsuccessful attempt at stealing the purse leads to the unforeseen events which follow. Instead of hauling him off to the police, Mrs. Jones drags Roger to her modest apartment, insisting that he wash his face. When they get inside the "large kitchenette furnished room" Mrs. Jones leaves the door open while pointing to the sink where the boy can wash.
The boy quickly contemplates his choices: "Roger looked at the door—looked at the woman—looked at the door—and went to the sink." For possibly the first time in his life someone is actually taking an interest him. It is a crucial point in the story and a crucial point in Roger's life. Had he run, he may have been committed to a life of crime and never again accepted the overtures of friendship which Mrs. Jones is now offering. He very much wants to be acknowledged and cared for. It was a principal reason why he was willing to steal in order to buy a pair of flashy shoes. He admits that there is no one at home at his house and, when Mrs. Jones tells him she will share her dinner with him, he becomes even more willing to please her even though he has ample opportunity to run. Because Mrs. Jones has treated him as a human being Roger is motivated to prove that he is worthy of her kindness and trust:

The woman got up and went behind the screen. The woman did not watch the boy to see if he was going to run now, nor did she watch her purse which she left behind her on the daybed. But the boy took care to sit on the far side of the room where he thought she could easily see him out of the corner of her eye, if she wanted to. He did not trust the woman not to trust him. And he did not want to be mistrusted now.