Earlier quoted context omitted.
It already did run it full bore for the past year and a half - US public is just not paying attention. At some point running it full bore will turn the US into Zimbabwe, currency-value wise. That will not reflect positively on the economy as a whole.
They have been buying up corporate bonds, which is not the same as printing money and spending it. They simply have to slow down and eventually stop buying bonds and as they are paid back, that money goes back of the ledger. I.e. it's destroyed.
As I said above, a lot of surprised Pikachu faces incoming.