"out of MH" spraypainted on sidewalks

[breaker's glider gun]

So, yesterday when I was walking back from a store, I saw "out of MH 10519 ft breakdown row 1" and some similar messages.
What do these mean?

[Entity Valkyrie 2]

I nearly read that as "out of MWSS"

[pcallahan]

They were "out of" mental health (MH) flying at an altitude of 10519 feet and had a breakdown on row 1. Based on the seat row, they were flying first class and probably wealthy. They were also clearly American because they didn't use metric. How they had the altitude to that precision is unclear. Maybe they asked the flight attendant, who would have had a very short walk from the cockpit to their seat.

I spraypaint cryptic diary entries on the sidewalk all the time. Doesn't everyone?

My other guess, assuming this is a real sidewalk message is that they are marking it to "break down" and replace. But don't know how to read those, so who can say.

[breaker's glider gun]

My other guess, assuming this is a real sidewalk message is that they are marking it to "break down" and replace. But don't know how to read those, so who can say.

that's my guess too, but idunno either. The first is probably not it because there were various numbers of feet and rows.