What I got from the Inquiries testimony in its totality was a lack of lifeboat drill, and an inexplicable lack of knowledge of the maximum loading capacity for loading then lowering of the lifeboats, and a complete lack of those filling the lifeboats to make sure they were properly filled in part by not getting steerage up to the boat deck.
Yes, I agree that a Lifeboat Drill would have been useful, especially for the crew handling the lifeboats themselves, falls etc. But it would be difficult to compute how much difference it could have made on that night in terms if the number of people saved.
As for "getting the steerage passengers up on the boat deck" it was easier said than done. While uncertain crew members might have tried to block some of them taking a particular route, I have never believed in nonsensical film depictions of large crowds of steerage passengers locked behind gates etc. The real problems were the
proportionately fewer stewards for the Third Class passengers, the language barrier in many cases, the long and convoluted route from the lower levels to the boat deck and confusion among the passengers themselves (searching for relatives, friends etc). As I have said before, 2 hours and 40 minutes can be "long enough" or "way too short" depending on one's perspective.
I also don't see any evidence that Nichols was killed in the attempt to open an E deck gangway door, or even a D deck gangway door.
I don't think anyone contributing to this thread nor other contemporary
Titanic enthusiasts now believes that Nichols or any of his men died during that Gangway Door trip. The only "evidence" (if one can call it that) for that conjecture was Lightoller's claim at the Inquiries that he never saw the boatswain again after he went off to carry the gangway door order. While that has been considered as a possibility in many earlier works, later research by the likes of Brad Payne (
Whatever Happened to Big Neck Nichols? ) showed that it was very unlikely. Apart from the fact that Nichols and his experienced seamen could not all have been killed in an attempt to open a gangway door with a flat, calm sea, occupants of Lifeboats #8 or #6 (never mind the order of their lowering

) would have seen and heard men in the water.
While Sam and I have a slight disagreement about the time that Nichols left on that errand and hence got back to the boat deck, I agree with him that after the boatswain returned, he was mainly active with the starboard aft lifeboats, working with Murdoch, Moody and probably McElroy. While Lifeboat #15 was in its final stages of loading - perhaps after it was lowered to the A-deck - Murdoch appears to have crossed to the port side and Lifeboat #10. IMO the others - Moody, McElroy and Nichols went forward to where Collapsible C was being readied for loading and Murdoch joined them after ordering Lifeboat #10 lowered. There are a few reports of the officers and McElroy being seen on the starboard side forward after about 01:55am; while there are no known sightings of Nichols himself after that timeframe, IMO people by then would have been more concerned about the time the ship had left and their own chances of survival rather than keep track of other individuals. Nichols might have been one of the men on the roof of the Captain's quarters working with Moody to try and free Collapsible A, no easy task with the port list.