My group plays TDM elusively, and afaik there's no way to back out without taking a loss. Attempting to do so even warns you that leaving the game before completion will count as a loss.
I play with 5 others and 3 of us have over a 3.0 kd/r, while the other two are all around a 1.15 kd/r.
In all honestly I think it's a combination of having good players and diverse gameplay among each player. I'm the turd of the group who camps it up and really, really, really likes to set people up to run into IEDs - it can get to the point where people simply avoid me and my general area, and I'll be lucky if I break 5 kills as a result. Our second strongest player is the annoying quickscopper who's killing people with BS shots, drop shots, head glitching, contextual lean glitching, etc. Our strongest is the uber soldat (MW2 style) who using nothing but quick/fast perks with a bulldog or combat knife and frequently malls down all 6 opposing players within 10 seconds - not surprisingly, he has the highest SPM, kill count, accuracy, and lowest rank among our group.
If you've been pubbing it alone and managed a 26 winstreak, that's pretty impressive given all the randoms on your team were likely mediocre.
Gonna hop on later when there's more people playing; really hoping to break 100 wins.