Now I've had a chance to think about it, and I can see why it had to go the way it went - with Tosh and the Hub gone, even the SUV, in fact all of the Torchwood technology bar the contact lenses, Jack really was forced to rely on his own wits to defeat the 456. His choice, at the end, was the only moral choice he could make, too; how could he ask someone else to sacrifice a child if he wasn't prepared to sacrifice his own? This, to me, showed how far Jack had come since his first encounter with the 456.
Let's not mention though the fact that he was prepared to hand over every child they wanted if they would only keep Ianto from dying... which kind-of flies in the face of his later actions....
And I do love the fact that after stealing a piece of heavy earthmoving equipment to break Jack out of the cell / concrete block, Ianto takes the time to don hard hat and high-vis vest. I can imagine it was his job to run the Occupational Health and Safety sessions in the Hub!
I haven't watched Miracle Day at all yet, but I'm planning to start this Friday.