The main problem, as I see it, with 158 aircon is that the units sit either in stations or sidings in the sun with the engines stopped. Naturally they heat up. Unit is started and, inevitably, air conditioning can’t work miracles, so it’s still warm. Guard then starts opening the windows and the game’s up. There’s plenty of times I’ve been on Liebherr fitted ScotRail 158s with the AC unit showing all green lights but the windows open. What’s the solution? No idea, the guards are probably trained but still get it wrong.
On the question of removing windows without breaking them, some stock in the US has a large red handle attached to the window rubber that can remove the window, I assume that’s what’s being thought of. Vandals here would absolutely love something like that. Less extreme, some road coaches in the US appear to have something where you can lift the window sill then the window hinges from the top as an escape route