Uncivil treatment to the staff

We went to Rocomamas Pineslope today and per covid regulations, we stood outside in a queue and waited to be assisted. After a few minutes, our turn came, and as we were writing down our orders I could hear a lady screaming. I didn't really mind all of that, but this went on for a while and I started wondering what was happening. I looked through their glass doors and saw a lady(seems like the manager) and 3 employees seated around the table. To my sight it turns out that the lady was the one shouting at these employees to the top of her voice a good 30 minutes. It was really a saddening and awkward moment. I mean she could have resolved whatever issue without reprimanding employees as if they're kids and 7 inviting us, the customers, to witness such uncivil behavior.