How about giving us the answer if we run out of time in practice mode...
Spent too much time thinking of the answer only for the practice to end and then not give me the answer. Quite unhelpful.
As auturoperezm points out, the speed trial is a spelling practice that rewards you for accuracy. This is really good for ingraining spelling, word order, and conjugations I feel.
The function you ask for is already there. If you want an untimed session of the material, try the button to the left that allows you to move through a review lesson without a timer.
Or do you mean staying in a practice until you have ten correct answers? It isn't a bad idea, but since you can already do untimed practice I don't see that it adds much.
I am not sure why there is resistance to have a summary page showing all questions I missed with correct answers - after the time runs out ... leave everything the same and the new feature can be optional so the purist can just skip it ... however I would like to see what I missed and learn from it