They'll do opposite to save price from falling.
Price is very close to breaking support while yields rise. They cannot afford to let Tbond mkt break. They might not talk about it but they will print to be able to buy and increase their balance sheet. If not all hell will break loose driving prices down and yields up. It is an "unspoken mandate" I hope not either. It will be really ugly if Tbonds start getting dumped across mkts. The bond mkt is 4x the size of the stock mkt.
You are right. Maybe they have something up their sleeve but it is scary. The tough part is that I think they have been "twisting" or selling short bonds to finance buying the long bonds. While this would drive short rates up as you said it would put a damper on the economy. There are 5 or 6 ways they can increase/decrease liquidity and I'm not sure I understand it all. Let's hope and pray they know what they're doing and also have the power to keep economy from tanking. I sure wouldn't want to be Fed Chair right now. Inflation protection seems to be important though.