Brain teaser on inception pressure cookers

[boenbrink]

Ok, so my room mate and I were talking and came up with this question.
What would happen if you placed a smaller pressure cooker inside of a larger one?
Both are rated for the same temp and pressure.
Would the one inside reach double the psi?
Would it blow up?

 

[Dr_Morbius]

Why would it? It's at the same temperature as the outer one and will therefore be at the same pressure.

 

[boenbrink]

So it should just double the pressure inside the smaller one?