And if this was the first baby, then 16 minutes to be pretty confident about what she was going to do. Didnt spend any time to hesitate, think twice or wait to get settled into her shift.
You make a good point for both arguments. If she is guilty, this makes it seem that she knew exactly what she was doing, her head was set, planned etc etc.
Then if that wasn't enough, she attempts to do the same, so shortly after with Child B...any normal person would think, 'it will look too suspicious'.
There must be evidence leading up to that point, was she edgy, did she make any online searches?