And this is the CGIAR SRTM DEM of the areas.
And here are calculated streams from a punched DEM. As calculations were done on an arbitrary rectangle, upstream area is lost, so this should be seen just as a visualization of flow direction. The basin boundary is changed to red. I had placed a no-data area in the heart-like feature to the right so that it would not fill to 939 meters and overflow into the Zambezi Basin. The bottom of that closed basin lies around 920 meters.
This is a detail image of channel by which the undrained basin would overflow into the Zambezi basin. The channel slopes toward the undrained basin, implying that the general flow is eastward, but not proving that it could never reverse. It might also be possible for eastward flows to bifurcate near the center of the image, flowing partly into the Zambezi.
Looking at the first three images, we see that this is a peculiar area, with channels that run close to drainage divides and with peculiar parallel features.