The were doing a full scale drill of taking a multi level building.
The strike at top and bottom simultaneously is a common tactic to split enemy forces into two fighting groups.
Also with a building that size its a real bitch to clear because literally EVERY space a man can fit MUST be searched. That means crawl spaces and every nook and cranny. Thankfully in these modern times a troop can do a thermal scan or use dogs to aid in the very labor intensive task.
The doors and windows were prepared ahead of time with plywood so that entry teams would have a harder task of entry.
In my view the ground team has had some training in entry before, but they do NOT look as if they have worked together on a daily basis and are most likely NOT a dedicated team. This was probably an "all hands on deck" type of scenario and everyone has to get involved. (Sort of like a MASS CASUALTY event a civilian hospital practices every once in a while.)
Room clearing is one of the most difficult tasks a LEO or a Soldier can ever do. I can't imagine doing it on that scale with people I do not know or have not worked with before.
Largest cordon and search I was ever on had over 150 soldiers involved clearing a small town all at the same time ... it was fucking awesome.
Noobs though they may be a training event like this is PURE GOLD for building a good foundation of experience and its crazy expensive to do. They should be proud to have been part of it and it WILL make them better prepared to handle a real world event.
All of my neighbours loved it. Screw people who think that military training exercises should be advertised to the public well in advance - that's how you get the crazies in there trying to interfere and put people at risk. And I don't know anyone who lives this close to the city who go to bed at 2130.
That was actually the first time I've seen them use the choppers with this particular building (recently purchased from Hillsong Church - God knows why they would want an abandoned building filled with squatters). I saw the first Blackhawk fly over my place then 3 others followed in formation behind it about 20 seconds later then started circling a block away from me. That's when I grabbed the keys and jumped in the Batmobile to go see the excitement!
And I agree on the noob comments.. for the blokes at the bottom, anyway! The ones who fast-roped in seemed to clear the top few floors with ease.
Interesting fact - they were hovering around in the landing approach for 2 of Sydney Airport's runways.. Sounds like an expensive training exercise!