Heya _DJ_,
likewise I can't find a way to bind that button. (old fashioned panic buttons are often hard coded and kept separate from us meddling kids for good reason I suppose).
But your question sure set off a train of thought.
I first thought you meant you were able to stop/break 'on-the-fly recording' (exciting! that would be brilliant) with a press of that button but in testing, the ! panic button doesn't stop on-the-fly recording for me.
For example, I test by playing 3 notes, pressing the ! button, then playing another 3 notes. The result is still an auto-saved 6 note 'recently played' MIDI file (not two 3 note files).
Maybe I misunderstand your question/usage (and you may have been meaning this - but while it's in mind and if Modartt folks are reading) I tried to make something like this happen in a few different ways but couldn't so far. (maybe someone has done this somehow?)
I currently resort to the still simple tried-and-true trick (2 clicks)..
By clicking the area where by default the "Blues Demo" appears, opens the list - and I do that to stop the 'recently played' routine (but a controller mapped option would be very cool). Ex. play 3 notes, click the list "recently played" shows a 3 note MIDI file.. and whatever you play next is a new file and so on.
But, it's still a routine, such as: Find mouse, hover, click, click again, back to piano.
A mapped controller button to press to send "save that improv to a finished file now" would be a very slick move (saving post editing and renaming chunks, or some other collection routines).
But, how to map that? No luck so far.. It might be a really nice addition to have the normal "stop" button in the inbuilt MIDI player to also trigger a break in 'recently played' recording - so we can easily map that button to do it (but that may introduce MIDI gremlins, so a unique button might be preferable).
I tend to just play and go in later to cut off beginnings and endings of those files, saving them to a 'somewhat more finished' pile for now - or if time doesn't allow this, just name them "jazzy-something-OK-near-end.mid".
Really mice idea you raised DJ, would allow instant real-time control (seemingly irrelevant until you add up the later editing) and would convert a lot of small-time cognitive interference back into staying seated and in the zone time - I'd certainly find it useful to trigger between performances and even if an improv goes in a different direction, single click to make sure I don't end up with one file with 2 or more things I'd rather turn out separately - would save a little editing fuss.
About 'panic button' in MIDI, it's probably something that could be good to map but I've found most implementations seem pretty hard coded (probably being a last resort thing historically, it's good to be known to be in one place only).
My digital keyboard has a lone "panic" button which I also can use to restart MIDI - but I'd probably want to leave that alone for mapping other uses, in case the day comes when I really need the panic function.
I'd like to map the 'record' button on my keyboard (it's internally set to be disarmed - but that button has the right name for this function
Food for thought.
Pianoteq Studio Bundle (Pro plus all instruments) - Kawai MP11 digital piano - Yamaha HS8 monitors