Yeah, that's why you don't want to do it(inflate debt away) but you can if you need to. It's never a bad thing to have a get out of jail free card on standby.
That's different. If the government prints money and spends it on goods and services in the economy to cause inflation, that would be 'inflating the debt away'. On the other hand if they print money solely to pay the debts, and they do not spend it on anything other than paying the debt, then that will not cause much inflation because the investors are most likely going to reinvest the money again, and it will not circulate in the economy. The result may not be much inflation at all.