To me this is an easy one; intent, means, and ability are right there staring you in the face.
The child gets shoved down into the corner and I take a crouched position in front of him/her (to better block anything coming his/her way). Draw and aim in and give one command to stop, drop what’s in their hands and get on the ground. Chances are that they run away and because of the child, I’d have to let them go. If they don’t, then I start shooting, working from the side to give the kid a better chance to run away in case I don’t get them all. This is an open and shut scenario and no jury in the world would convict you of anything. Shoot, I doubt there is a DA that would even charge you.
Doing what you've done, gets you what you've got.