You have misunderstood how to construct subquery conditions.  (But don’t worry - I think I see your confusion)

You have put the subquery definition in the property called “Subcondition logic”.    That is not the right place. 
Push the new condition icon that appears in the left hand panel to expose a second condition builder. 



The subcondition logic property is used to define how multiple subconditions work together.  You’d expect a statement like this there:   (1 OR 2) AND 3 AND 4

So close.  You are so close… 

Perfect! Totally solved my problem. For future reference, what should the Subcondition Logic field be used for?

The subcondition logic property is used to define how multiple subconditions work together.  You’d expect a statement like this there:   (1 OR 2) AND 3 AND 4
Much like condition logic set for the model as a whole, if you don’t put anything in the property - Skuid assumes they are all tied together as AND statements. 

Got it, thanks Rob!