Sword disappears: wipe
Shit I did too much damage to Crota on the second sword: wipe
Some idiot say go to the sword bearer when no rockets are launched: wipe
Then we clear it.
It's how my runs usually go and it costs a couple heavy synths. I imagine it's worse for a random group though.
Random group is your problem. And that does suck sorry. As far as sword disappearing, it's because a cursed thrall blew up next to it. Don't take out sword bearer with rockets and that won't happen. Also, first knee of every sword should be taken with primary. No heavy needed there either. And three rockets after he stands up with everyone else's primary will take him right back down.. 3, 6, 9..
There's also no such thing as "too much" damage on the second sword.