I was one of those in the party when it dropped us all out, it was the one before the last wave, we had more than enough lives to do it, it was a dead cert to get it. I have done the achievement on a number of accounts and never had a problem like that before, i would say i have done it 6 - 7 times, if someone had left then fine it would have been a disconnect and had to deal with it, but the fact no-one did and we all did very well i feel cheated out of that achievement. Although i will be doing it tonight at times like this Bungie should step in and investigate, if someone has enough lives (25) for the last wave then surely its a dead cert to get it. I blame the servers not peoples connections, we all made sure that we had nothing but xbox's on, all phones off, hard wired to modem/router. Not detectable lag until IT decided to end the game and return every single one of us back to lobby.
What the guy forgot to mention is we had that happen the day before too, that was Total Length: 01:44:35 Set: 4 Round: 3 Wave: 1
Two days running i have had the same happen, before anyone says it down to my connection i know its not as i test it and have a download of 6mbps, upload of 0.38 and a ping of 65. I have never had a problem on Halo 3.
Feel better now i have had a rant!!!, as i said i will try again tonight and if it drops everyone again then i may well just give up on it, no point if the servers cant cope with 4 x people playing a game!
Jon