The following contains movie spoilers

At this point of the movie, Selma (Björk) is being taken to be executed in the gallows, which are 107 steps from her cell.
Brenda (Siobhan Fallon Hogan) is a sympathetic prison guard who talks to Selma, and encourages her that she just needs to walk 107 steps to get to the gallows, counting them out and walking with her.

Selma, as is seen in the rest of the movie, deals with hardship through singing and making a musical out of the situation.