SVB failed so quickly the Fed couldn't go through their usual process. The Fed had to throw out the rules and effectively stare that FDIC limits don't matter and all deposits are fully insured.
They were then so concerned about First Republic failing quickly after SVB that they in all likelyhood helped orchestrate a $30B deposit by major banks to help provide liquidity. That move is extremely odd and really looks a lot like market manipulation and collusion. They also must have known that was a short term measure to delay the failure until they could let the smoke clear and find a buyer, banks would have provided First Republic loans or invested in the bank if they had any faith in it's long term viability, depositing cash is just a show of force.