There are many reasons for Trump to stay out of this right now -
It is politically benefitting him - he appears to the the victim to his base and increasingly to independents
The longer the DOJ obstructs congress the worse it looks for the Special Counsel investigation
It is a matter of timing - he knows what happened (there is little doubt in my mind he already knows) so he can choose when and how to declassify documents and put out information that benefits him
I would bet there are things we are not yet aware of - i.e. prior admin involvement, etc etc. As long as this is hanging over their heads (not Trump) they are amazingly quiet contributing to the rudderless lurch to the left within the DNC
There are also likely some investigations behind the scenes that have not leaked. Trump is a fighter like we have never seen before so you know there are some counterpunches coming and as of right now he looks to be above it all
It will come out in good time - nobody trolls the media like Trump and he is a master of controlling the news cycle. Have faith.
Bingo