Another survivor of the ordeal, Salamatu Bulama, 20, said that a number of the girls and women they were with had died, as the military tried to free them.
Some of the women had to walk to safety, as there were too few vehicles to transport all those rescued.
But three were killed when they strayed into the heavily mined surrounding area, triggering a land mine.
About 10 others were killed when an armoured personnel carrier drove over the bushes they were hiding in. Further women are thought to have died from stray bullets.
Ms Musa and Ms Bulamu are among 275 women and their children who were freed by Nigerian soldiers and are now receiving medical treatment at a refugee camp on the outskirts of Yola, the capital of the north-eastern Adamawa state.
Nigeria's military says it has rescued almost 700 captives of Boko Haram in the past week, suggesting the tide may be turning against the militant group.
It is unknown if any of those rescued are the girls who were taken from a boarding school in Chibok last year, which sparked the “bring back our girls” campaign.