Your assumption is not entirely correct.  Isn't the part of Physics in Chemistry acceptable? When you deal Chemistry filtering out Physics, it must show its 'individuality', right? If not, what is meant by Chemistry...? No matter whether it is science or non-science, you can find this 'individuality' in each subject.  So I can't see anything wrong in it.  

Physics deals only with mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms. Please note, 'mind' is not included in these branches. 

Biology, neuroscience and psychology are related to living things, an important part of which is related to the mind.

> Is there any reason why special sciences like chemistry, biology,
> neuroscience and psychology would need their own immutable laws that
> aren't reflective of physical laws ?



There must be something higher than Physics that connects all things (living and non-living) in nature. When mind plays an important role, the dimension of these subjects change. 

So this is a moot question.