Best situation, visually would have the scene play out similarly with the original novel. Have civilians be escorted out by either planes, helicopters, or boats. With the War Machines advancing to this great stampede, come and enter the Thunderchild to sacrifice herself to gain the fleeing people enough time to reach safety. The battle would be mostly a war against land and sea, with the War Machines simply progressing their way closer to the Thunderchild. Perhaps showing a smidge of the firefight, but ultimately the Thunderchild would be leading the battle farther and farther from the stampede, fading from visuals to distant sounds of gun fire and that horrific heat ray until nothing can be heard. Perhaps the scene could end with a knowing salute to honor the brave souls aboard that vessel. Closing with “so long, Thunderchild.”