[D-fendr]

How can you have physical laws/forces where there is no universe, i.e. nothing?

Why can't you? Although it would be moot in practice with nothing for the laws to act upon.

But, imagine this: Assume you create a perfect vacuum in a container. Into this container you then put oxygen, heat and fuel. A fire results.

You did not put the physical laws into the container. The choices we have are that the laws are contained in the atoms – a problematic reiterative problem I think – or that the laws exist everywhere in the universe even where matter doesn't.

[Heartlander]

‘Nothing’ can only equal ‘nothing’. What physical law(s) applies to nothingness - particularly as a first cause for the physical?

Honestly, I’m more curious as to the point you are making…