Did they fail to recognize it, or merely judge that that outcome was better than the alternative or that they could turn it down before the inflation got out of

Did they fail to recognize it, or merely judge that that outcome was better than the alternative or that they could turn it down before the inflation got out of hand? It seems utterly obvious that a high level of money printing without a matching increase in supply of goods and services would eventually lead to a dramatic increase in inflation. It's less obvious exactly when that would start and when it would overshoot a comfortable range.