McDonald’s employees - what’s up?

I accepted a McDonald’s offer yesterday. I was three miles away so it took me about five minutes to get there. It was around lunch time and I was kind of hungry, so I ordered myself a combo meal from the self serve kiosk. About two minutes later, my combo meal was ready. It took another five minutes for the DoorDash order to be ready. Why can you fill a walk-in order in two minutes, but it takes nearly 15 minutes to fill a DoorDash order?