Besides the “run without screen refresh” button, there could be a check-boxes for return. Once a block that has the return checked, the block has a new draggable besides the inputs, the return block, which would have the rounded input selector, and the block itself instead of being a block, it would be an operator-like block. Whenever the return block is used inside of the block, the block stops its script and has it output be whatever is in the return.

So basically outputting something from custom blocks without requiring them to set a variable to something?

say (join (join[I'm ] (get distance from goal :: custom))[ units away from the goal.]) for (2) secs

define get distance from goal
code to check distance :: grey