  Starting from the diffusion equation at beta random matrix hard edge obtained
by Ramirez and Rider (2008), we study the question of its relation with Lax
pairs for Painleve III. The results are in many respects similar to the ones
found for soft edge by Bloemendal and Virag (2010). In particular, the values
beta = 2 and 4 (but not beta = 1) allow for a simple connection with Painlev\'e
III solutions and Lax pairs. However, there is an additional surprise for a
special relation of parameters where a simple solution of the diffusion
equation can be obtained, which is a one-parameter generalization of Gumbel
distribution. Our considerations can be extended to the other Painleve
equations since the corresponding diffusions are in fact known as nonstationary
(imaginary time) Schr\"odinger equations for quantum Painlev\'e Hamiltonians.
We also track the hard-to-soft edge limit transition in terms of our Lax pairs.
