Hmmm, I guess I see this differently. You don't mention what rules were in force at the event, so I'll assume it's the PAPA/IFPA ruleset. In this case, I don't see any of the documented stuck ball exceptions being applicable: the ball is not directly over the outlane, no portion of the ball is below the outlane post, the ball is not stuck on an inlane/outlane post/guide (because there is no inlane). The ball is just stuck in the vicinity of the outlane. The TD may try to free the ball through nudging, else open the machine and place the ball on a flipper of the TD's choosing.
However, if you really feel that counts as "stuck on an inlane/outlane divider" (the only interpretation I could see justifying a drain-out here), then yes, those rules specifically mention placing such a ball into the outlane, which would cause the ball to be routed to the right flipper, and the gate closed. I would say in an outlane stuck ball situation, it's always appropriate to trigger the outlane switch, since on some games ( ::cough:: High Hand ::cough:: ) that could be an important switch.