2 units (in this case houses) down and 2 across (a perhaps intentional misinterpretation of the original slightly ambiguous statement).
Reasonable to assume down and across are perpendicular directions.
Let's pretend space-time is Euclidean.
How far away is the listener from the sneeze?
Pythagoras, our faithful companion, guides our understanding...√(2²+2²)=√8=2√2