There is no way the answer is 7 million. Now what I did may be wrong, but I know 7 million can't possibly be right.

You have 10 soldiers. For the first row you are told out of the 10 soldiers, to order 5 that will be placed in it (as order matters, not uniqueness - since you are asked the number of WAYS the soldiers can placed): 10P5. In the second row you have 5P5 ways of arranging the remaining soldiers. Therefore (10P5) + (5P5) = Number of ways to arrange 10 soldiers in two rows.