Fyi the help next day from a different supervisor was such a contrast vs the day before (when later it turned out that MH had used marking me as no show to hack my "we can't touch it" ticket by pulling all their segments out of it -- including ones months away -- as well as a seemingly random aa segment even later. Fortunately the aa rtw desk sorted that before I went back to the airport).

I found a supervisor in the office where she calmly listened, then focused on what might help rather than on it not being MH's fault. She was able to open up an inop seat whilst the rtw desk were on the phone so it could be grabbed and allowed me to get ticketed and checked in. She was clear to note I might not get a business seat (if it wasn't safe) or a fully working one. She then diligently followed up with engineering to (successfully) get an ideal outcome, and finally checked on me in person before the ground staff left the plane.

lessons that come to a tired mind;
* rememeber all risks are heightened if a flight is delayed
* the main airport info desk is likely to have substantially more experienced and knowledgeable staff vs a smaller one
* if you get a supervisor on your side, especially if there's less rush, they have a fair chance of pulling a rabbit out of a hat