During a run with my LS up to the last boss we usually only have 2 deaths and one of those would be by complete accident if it were to happen. While actually fighting the last boss is a bit different because of learning the fight through progression. We may see several deaths but then again everyone in the party has atleast R1 so getting people up has yet to be a problem for us. By the way requiring people to use Vent while doing these (even if they don't have a mic) ups your chances of not dying drastically.