As I watched the videos of the individual running around in the traffic, the first thing that came to mind was, “what are these people doing, filming it” There is no need for you to risk your life to film something and just like a moth drawn to a flame, you could get burnt!
If you hear crashing, shouts etc. and you run to the window and see people lying on the ground injured, a crashed up car and a person with or without a beard running around in the middle of the street, you need to immediately get away from the windows and the exterior of the building and seek shelter in a safer location. That Jihad nut bar could have had an explosive vest on or had his vehicle set to explode.
Windows would shatter and come flying in as a million sharp projectiles. Then if like other times, he had ball bearings mixed in with the explosives, they would shred a person apart. So between the pure shock of the blast and all the debris, you would be at serious risk of injury or worse.
Most modern building consist of steel columns and plate glass and offer no protection and in fact, enhance the effect of an explosion. Even an older building with thick concrete columns are not safe from a vehicle bomb. So please stay away from the perimeter and seek shelter towards the center of the building. Keep yourself safe so you can make movies with loved ones!