I'm interested in whether this is supposed to be an in-game event, or if it takes place significantly before. Note Kat's lack of "robot arm". I can't imagine it would be a production oversight, considering how much money they've thrown at this trailer. (Also note that she takes the hit from that Banshee primarily on her right.) If it takes place before, that also means N6 isn't the one who plants the bomb, and that this doesn't even take place on Reach.
Or maybe it's just like the "Believe" campaign, in that it differs significantly from ingame events and is just there to be a flashy ad.