Broken gearbox noise?

[ProjectZS]

Anyone ever heard a noise like this before coming from their transmission? This is on an M32 gearbox. Goes when clutch is pressed. Seems to engage all gears however I’ve not driven it since it did this, car is running over 500bhp and went without warning when it went into 3rd gear….I know it’s A guessing game until the box is out, but wondered if anyone else had experienced similar noise before and what their findings are? I’ve drained the oil and it seems metallic like there’s swarf in there, but was kinda hoping for some large pieces of gear to add some clarity….