I have an A320 type so let me try to guess what happened in the A330. The airbus is... different. You can displace the stick 100% in any direction and it wont bank beyond 67 degrees, pitch up more than 30, or pitch down more than 15. It wont overstress because the stick controls G-forces through a closed feedback loop. It also has high-speed protections where it will automatically apply positive G-force to pitch up in order to slow down. The pilot cannot override these protections. You can do whatever you want with the stick and as long as the computers are working and getting good data the aircraft will not stall, overspeed, overstress, or roll upside down. If you get too careless it will even run the engines up to full takeoff thrust and microblog it to you. These protections were working the whole time the captains stick was deflected 100% nose down. The system isn't perfect and it allows some overshoot, as you can see, but at least the protections kept it within 17 degrees nose down and mach 0.9.

Now to the story at hand, the captain probably didn't realize his camera was wedged between the seat's armrest and the control stick as he moved the seat forward. I can only guess that he assumed the strange attitude was the result of a computer malfunction because he considered turning off the computers that provide many of the protections I mentioned. Good thing he didn't. Now the first officer gets into the cockpit and probably tosses a wtf glance at the captain but upon getting one right back he decides to use his own stick. The sticks in the bus aren't mechanically connected but, just like with mechanically connected sticks in antique Boeing aircraft, their force inputs are mathematically summed. Yet unlike mechanically connected sticks, displacement isn't transmitted across the cockpit so the first officer wouldn't be wise to the fact that the captain's stick was full forward. Luckily the bus engineers thought of this. When the first officer pulled his stick back the computer would have noticed both sticks moving and it would have announced "dual input". This isn't a microblog or a gentle woman's voice. It's a pissed off dude trying to talk some sense into you. At that point the captain probably looked at the palms of his hands to make sure they weren't on the stick. He probably showed his palms to the first officer too. At that point they had two heads working on the problem and it wouldn't have taken them too long to find the camera.