I have duplicated the data dynamically using technique #3 in The Cross Join Collection so there is one row for each open and close date.
SELECT d.* , l.[Status] , IIF(l.[Status] = 'Open' and d.[ESCALATION_DT] is not null, d.[ESCALATION_DT], IIF(l.[Status] = 'Open', d.[REQUEST_START_TIME], IIF(l.[Status] = 'Closed', d.[Closed_By_TIME] ))) AS [Date] FROM [data$] d, [lookup$] l
Having one row per close and open date makes it easier to visualize. I hope this is something you can use. If not, I hope this triggers other helpers to share a simpler and more elegant solution without custom SQL.
Jóhan a.k.a. Kettan