Duplicates Across Columns is looking for runs of rows where two or more columns have the same value in the same row.
Here's an example:
The red cells in rows 603 and 604 have the same values in the columns Erythrocytes and Potassium.
I don't think Explore Patterns has an option that would detect runs of rows across columns.
Instead you could create a new column that concatenates the values from your two columns and then the Univariate Runs would detect them.
Alternatively you could use Tables->Summary and group by your Time and EventCode columns and you'll get a table (linked to the original table) that groups time and event codes.
-Jeff