What is the significance of the following lines? "Travis: I just came in. . . . Ruth: To the doctor" (act 1, scene 2).

In A Raisin in the Sun, Lorraine Hansberry depicts an African American family struggling to make ends meet going about the mundane events of their lives—waking up, sharing a bathroom with other families, going to jobs they find unfulfilling, and getting the never-ending chores done. Day in and day out, this is what they do. However, the tension in the family has been building; it seems as if the walls of their too-small apartment are closing in on them. As they attempt to maneuver around each other to get to their work, their schools, and their errands, they find their frustrations and resentments flaring up more and more often. As the pressure builds, it seems like they may explode. Later in the play, Walter refers to himself as a “volcano,” but this can be applied to all of these characters: they have let their dreams and frustrations build up for too long.
When a $10,000 insurance check arrives for Mama, a check that everyone has been waiting months for, every single character in the play has placed his or her hopes on that money in the desire that this check may help transform their lives. Most obvious is Walter, who announces to everyone what he wants to do with the money. He wants to use the money to open a liquor store and be a businessman. The others decry Walter for his desire to tell Mama what to do with her own money, especially since Mama is clear about not wanting to support a liquor business. However, the others also have desires for this money, although they do not announce this openly as Walter does. Beneatha states that “it’s Mama’s money” and that it is up to Mama to choose what to do with it. But at the end of the play, when Beneatha finds out that Walter has lost the money, including the $3000 set aside for her own schooling, we see her devastation at not being able to get that money. Ruth also has her desires for a better situation for her growing family. She is pregnant and is terrified at how they will manage with another mouth to feed and shelter. She is also terrified at what is happening to her relationship with Walter, and she is hoping that this money will help solve some of the problems in their marriage. At only seven years old, Travis seems too young to have an idea about what to do with the insurance money, but Walter is clearly grooming him to follow his footsteps and dream big.
Can $10,000 change life for the Youngers?
The day the check arrives all of their dreams suddenly seem possible. Suddenly, they no longer feel confined by the dimly lit and cramped confines of their living room. Life opens up. This money seems to make space for their dreams to breathe. Their dreams have never seemed more real than when the $10,000 insurance check finally makes it inside their living room.
But for Mama, this check does not represent a dream. It represents a death. This money is the insurance benefit due to her from the death of her husband. When she finally gets the check, she is overcome with grief. This check came from the blood, sweat, and tears of her husband, who worked himself to death for his family. He was a man who was never able to “catch up with his dreams”; instead, his dreams seemed to “dry up like a raisin in the sun.” This check, which brings the rest of her family so much joy, brings her sorrow. She also is sad because she feels a growing separation from the rest of her family; she cannot understand why they are so fixated on this money. But she is not one to drown in her sorrow. Like her “raggedly-looking plant,” which holds on to life despite the poor environment, she knows that she too must hold on to life and do whatever she can to help her family and to make their lives better. This is just what her family is counting on.