I really don't think Gerry was intending to make a part 2 to
Expect the Unexpected.
I think the only reason there is a part 2 is so Gerry could introduce the other characters in Terrahawks who didn't make it in part 1.
i.e. The Battle Tank, The Cubes and Hudson.
In other words I don't see much point in this episode, but it's still pretty good.

After the field is broken, what happens to the Cubes?

How come Zelda's attack in part 1 killed 2 Cubes, but they only have a funeral for Number 13?

Is there any reason story wise (NOT productionwise) why this episode cannot lead into Thunder Path rather than Thunder Roar?

Why does everyone question whether or not Zelda is only hostile because Zeroid 13 might have attacked her first? Hello people? She obliterated the Mars Base, remember?

And how could Ninestein for one moment believe Zelda might not be hostile after what happened in part 1?

It wouldn't work if Path came after Part 2 because Sram was already released from suspension in Part 2 and in Path he was about to be released.
In Part 2 Sram was lying down, in Path he was standing up.
Yung-Star was introduced in Thunder-Roar, if Path was ep 3 then Yung-Star and Cy-Star would come out of nowhere.
And at the end of Part 2 Zelda said she was going to give her monsters a chance to face the Terrahawks but Path wasn’t about fighting the Terrahawks it was about crashing the Overlander into the oil refinery.

There's an interesting line from Ninestein about the cubes looking a bit 'dicey' to him.