Since someone mentioned transferring, it triggered me to remember that both times when I was transferring to my DOH-KUL flight (after flying in from JFK), J passengers were directed to a door that took us right back to the terminal. No additional screening/passport checks no nothing. It was so delightful. When I was flying back to JFK I did have to put my carry on through the machines again but I don’t know if it’s because there was no business only disembarking and we were mixed in with economy class because they didn’t open the front exit doors. Even so it was relatively painless and they also did have a special line for First and Business. I never did have to get on any busses
