Only going to be a problem if real estate prices crash, or if millions of people start to empty their accounts. Things did get a bit dicey when people were emptying savings accounts to buy treasuries and bonds that were paying out over 5%. That got banks a bit worried.
The fed can steer clear of disaster by buying hold to maturity bonds back at face value, just have to have the right strings attached to them to ensure that once the banks solve their liquidity problems, they repurchase those bonds at the same rates and maturity dates. Ensure they don't use those funds to pay bonuses, make new loans, or purchase more profitable investment instruments. Give those banks liquidity when they need it, without the penalty that would create doubt in the financial system.
Branden