These ramp incidents (opening doors and approaching the plane inappropriately) happened all the time at Envoy (like around monthly). Multiple times I had someone open the cargo door with #2 still running (short taxi so not enough cooling time). The standard op on the 175 with APU inop is shut down #2 when you can, and then shut down #1 when GPU is plugged in. There is never any reason for a ramper to approach engine #1 even with APU inop.
The only reason I can think of was that ops knew plane had inop APU so they wanted to plug in PCA as well as the GPU. That connection is under the plane and you pull it right in front of #1. This is speculation and I don't know for sure.

Some ambulance chaser lawyer is gonna get a huge payday soon, this is a systematic issue with rampers and their training and culture of fear and rush, and I bet AA will settle for 8 figures. The ramp is a dangerous place, but their training is almost non-existent.