We did the task in ten minutes.
I am pretty sure that it means
1) It took us ten minutes to do the task. (We spent 10 minutes doing the task)
However, I see no obstacle to suppose that it may also mean
2) We did the task after 10 minutes passed.
(That is, "We did the task in ten minutes after we were told". Hence, we might have done the task in 20 seconds but we had been waiting for 10 minutes before we started doing it.
Do you agree that the second meaning which I infer is possible?