If you can eject and survive, surely it'd be an idea to pop that particular helmet / breathing gear on, then NOT eject lol.
It's a gamble... Put your space helmet (REMLOCK*) on and stay in your breached cabin, hoping you ship can limp away and not blow up. Or, just get the hell out of there, and see your ship survive without you.
Maybe an option would be something you can buy so a cabin breach really isn't an issue on its own - overall hull integrity would be a concern though...
This is the thing, you could potentially wear a full, space-worthy suit in your cabin. So, unless your suit is breached too, you'd be fine. However, how will the game simulate the more movement-restricted nature of piloting while in a full space suit?
Plenty of options for further discussion no doubt. I'm thinking, at the moment, canopy breach = get out or die, simple as that.
Scoob.
* Assuming you have a full suit on as well of course...