I've worked in dozens of offices, mostly in the northeast of the US, and I've never heard the phrase "at work unit."
I don't know what it means or how it's used, so I can't tell you which word to stress.
Even without "at," I've never heard a workplace called a work unit. Maybe people do call it that in some places. But adding "at" just renders it meaningless. Maybe a work unit is an employee. (But the phrase still wouldn't make sense.)
It would make sense if you got rid of "unit." We all know what "at work" means.
It would also make sense if you added a word, like "at your work unit" or "at a work unit." Or even "at work as a unit."
But that's not what the recording says. Your source might not be reliable.

English Teacher