If ever we play as a team, I will show you what I mean. Just make sure to remember you and every other member of the team is responsible for a specific area and task. As a bomber engineer, I usually take care of the zombies in the engine room.
Or you can play on your own, and do all the work yourself. You can equate that to the 2-man run of KASE. Soloing one side is possible, but good luck trying to kill EVERYTHING while still killing the probes. It is tedious, and it takes forever. But go with a team who knows what to do, get everyone on a certain task, and the job goes by quickly. Problem solved.
In Left to Die, you have clear out the rooms one by one, doing it by yourself. Then you have to activate all the consoles by yourself, talk to all the contacts by yourself, fix the warp core by yourself, deactivate force fields by yourself. Then repeating the mission, you have to do the same thing again, over and over and over again. I think you get the point. If you are soloing it, you (or at least I myself) can only stand two consecutive runs at most before you (I) just don't want to do this ANYMORE! It is much more efficient and actually FUN if you go with a team.
It is not just that. Case in point, I have a friend in the Canadian Army who was also sent to Afghanistan. He and his wife were injured and discharged. A few months later, they were forced BACK INTO the Army, and sent to Afghanistan again. The following week, on a routine patrol, they were ambushed and his wife was killed right in front of him. The Canadian government then asked his sister to adopt his children because he supposedly could not care for them.
He has since been discharged and AGAIN forced back into Afghanistan. He no longer has his children. He no longer has a home to come home to. He has lost everything because of a war that should never have involved him or Canada at all. And now NATO is sending troops there too.
What if that had happened to me? I don't think I could live with myself if that happened.
You can say a lot of things about the hippies but they were right in wanting peace.