This issue picks up right where the last one left off, with the Talokian military bent on destroying the Legionnaires and Shadow Lass. Superboy observes that there are thousands of them, and he seemed nervous. Perhaps Shooter had decided that, at 15 or so, Kal-El was still depowered to 1938 levels. That might explain why, in this story-arc, he has Superboy schlepping through the desert like Lawrence of Arabia. At the very least, his super-speed must not have been up to Barry Allen levels yet, or he would have been able to quickly dispatch all those soldiers.
Of course, he is able to make it through the time barrier into the 30th Century with no troubles…