They do this every once in a while. I recall them doing this some years back in NYC.

Similar to military trainings done in cities. Remember the training in Miami almost ten years ago? https://incogtube.com/watch?v=j1BhRNfY1lo . This was in LA more recently: https://incogtube.com/watch?v=cISSyQkm1Ug There are many other examples from other cities over the years as well. It's not exactly uncommon.

Easier than building mock cities to train in urban, at home environments but still scary to witness and always has people wondering, "What if..."