Decided to talk to young moms who are aware of my gun interests and also pretty sensible warrior types. Uniform opinion is to get the baby out of Dodge, out of the line of fire, never leave baby and call the cops.
No tactical movement here - kid is saved first. They will handle their end as best they can.
Also, some opinion that a good mom would be breast feeding the kid anyway, which obviously depends on the age of the kid.
A basic principle of this which many 'tactical' movers seem not to understand is that if you can see the muzzle of the gun, the muzzle of the gun sees you and baby.