After beating lvl 10, I stood on top of a grey box, near the left side, under the garage where most players take cover. Selected boneyard for next survival, along with another guy. Instead of going to invite players screen, it prompted "unavailable....join(or go) online " or something like that. I ended up in the box, but accidentally walked out of it before i could take a photo. After that, i tried starting up the mission again, going on box and quitting from phone, but it just put me on my motorcycle up on the hill above. Going to try and idle out next time to see if that would work.