Also on an earlier post someone commented that fan blade failure can/must be contained but disc failure cannot be. Is that an absolute because the engineering cannot contain the energy or is it economics of not having a ring of titanium 'armour' around the more vulnerable higher energy hot components?
Blades need to be contained in the event of a seperation anywhere through the engine including turbine, however if its a wheel failure that's generating energy at TO power that's pretty much impossible to contain (per Sioux City DC-10 and that was at cruise setting). Failure risk mitigation comes down to design, manufacturing and operating stats which are now pretty phenomenal for big turbines. Trend now is to go for blisks to avoid the trad fir tree root connection but now you have one single lump of very high energy. I'm sure the regulators do the maths.
It would appear the failure was uncontained to a certain degree given the cowl and ancilliaries damage but I haven't seen images to determine whether it blew through the wing. The WTB fairing damage is clearly heat rather than penetration, presumably the fuel source was damaged fuel system at the point of exit for whatever exited. The positioning you can see does initially appear to be relatively forward suggesting IP or HP compressor rather than turbine.