I'm sure 'the industry' will take measures to prevent this happening again. As long as it doesn't cost too much money.....
I like the US model, where an ATP needs 1500 hours. Nut jobs might be discovered by then, but it would cost money.
Better Terms and conditions, treating pilots with respect, might help, but that would cost money too. Right now pilots have the same status as fuel.
Stopping 'pay to fly' might help recruit better, more motivated pilots, who want to fly because of a genuine interest in the job, but it would cost money.
Putting a hostie in, while you take a piss: free. Will be done!
Personally, I try to never leave the cockpit. I'm paid as PIC to look after everything, all the time. Can't do it from the toilet. That's how I see it anyway, and isn't really a reflection on the F/O.