I read about that the man demanded the dog be moved out of the way first, then put the gun to the nieces head and demanded the baby.
The lady, Donna, was in charge of someone else's child as well as her own and as the kidnapper had the gun to the nieces head she could hardly refuse to hand over the baby. The fact that she complied with the kidnappers wishes to save the life of her niece doesn't imply that she wanted to hand over the baby or that she handed her over too easily.
If I had a child I wouldn't want to hand it over to a stranger with a gun, and I would fight to the death defending either of my precious nieces, so I guess I would do what Donna did, since she did have to choose and I haven't had to.