Q: "A person is washing their hands in a white sink." Does this mean that "A person washing"?
A: yes

Q: "A couple sitting on the steps with their heads down." Does this mean that "Two people are on the steps."?
A: yes

Q: "A group of drummers are walking down the street." Does this mean that "The band plays in a gymnasium."?
A: no

Q: "A woman in jeans and a blouse is carrying a blue shopping bag and leading a child through the mall." Does this mean that "A mom grocery shops with her child."?
A:
it is not possible to tell