The sequence of events don't add up.

I suspect that you might have been told that (about not walling-off the door between up and down) because if they don't have a way out from downstairs, in the event of a fire, they have to be able to get out. 

You can meet local investors by registering to attend real estate events in your area: https://www.biggerpockets.com/forums/521-events-and-happenings6.

You can meet local investors by registering to attend real estate events in your area: https://www.biggerpockets.com/forums/521-events-and-happenings6.

You can meet local investors by registering to attend real estate events in your area: https://www.biggerpockets.com/forums/521-events-and-happenings6.

You can meet local investors by registering to attend real estate events in your area: https://www.biggerpockets.com/forums/521-events-and-happenings6.

You can meet local investors by registering to attend real estate events in your area: https://www.biggerpockets.com/forums/521-events-and-happenings6.

Customer service doesn't even begin to describe this chain of events; this is guided missile level sales follow up and over the top attention to detail and customer attraction.

You can meet local investors by registering to attend real estate events in your area: https://www.biggerpockets.com/forums/521-events-and-happenings6.

@Brian Ploszay definitely had some great insight.To expand on his first point, I think a "triple net lease" would be a good model to try to follow.Also, make sure that in the event your optimal tenant (drug rehab) were to move out, you have multiple exits to help you sustain any market downturn.