The quick fire was the one where the situation was a unit being overrun, and we needed to get artillery shells into the area to let the attackers know that focused artillery was coming within minutes.
The exercise was that you are driving, and suddenly you have to stop, and the second that you can get a shell into that engagement, you fire it, and then you proceed to improve and refine your firing position.
My section used to win those kind of things, and it seems like it took, far, far less than 10 minutes, back then I would handle the over 200 pound spade myself, to free up an additional digger.
That seemed to take about 10 minutes, but we had the gun laid by then.
In the exercise you describe, how did you proceed to lay the gun?