Consider the tile with the 2x2 block of red-dashed line impassible terrain on Training Ground:

Can a figure without Mobile use Jump Jets to get inside it?

I don't see what would prevent this, but then the figure would be stuck?!

Can an ugnaught place the junk droid inside it?

Same as above. Two squares separated by dashed lines are still adjacent, so you can place the junk droid in that square. But he'll be trapped! Poor junk.

Edit:

Actually, this rule from Impassible Terrain prevents these scenarios, I suppose:

Consider the 2x2 block of blocking terrain on Nelvaanian Warzone:

Can a nexu pounce into the middle of this 2x2 block?

I think the Counting Spaces rule means it is impossible for you to count to or through the blocking terrain. Therefore, you can't end up taking up the whole 2x2 block.

Mobile does nothing to change the Counting Spaces rule, so blocking terrain is no good.

You can't count spaces through a blocking space, but you can count spaces into a blocking space for the purposes of targeting and interacting. You can also be adjacent to a blocking space for the same purposes.

Pounce is neither of those, and you're correct that Mobile does not apply to Counting Spaces.

You would not be able to *Pounce* a Nexu into the *center* of the 2x2 Blocking Space, but you could use Mobile to just move there normally. Alternately, you can Pounce into a portion of the 2x2 block, by counting spaces to a legal square and placing the Nexu in some of the Blocking Spaces.

Sounds like that should be clarified. Seems silly that a Nexu can't pounce there, though pouncing to an adjacent space should be enough to cover most situations. There's probably some really obscure setup where all the other spots are blocked by figures but i guess that's rare.

As for jump jets. It technically says you can't ENTER a space with blocking terrain. So once you're in there (with jump jets) you could still leave that space. There's no 3x3 blocking terrain so you should always have one edge or corner that leads to a non blocking square.

You can never be in a space if you can never enter it. There is no way to get into a space other than entering it (via move or placement).