Impressions based on available video and photo material:
A. Righthandwing top panel:
At one stage in the video’s there is a major explosion on the right hand wing side. A large dark object is seen flying/blasted away. Some suggested that this was an escape slide.
Looking at the present state of photo and video material, my impression is that it is far more likely that it is a significant ‘part’ of the ‘top panel’ of the righthand wing. This ‘part’ roughly running outward from the wing root in spanwisedirection upto the middle of the second slat right from the right-hand engine. Fuselage-lengthwise this ‘top panel part’ running roughly between rear and front spar. The outer slats probably not even ‘hit’ during the explosion. So all in all a very large ‘toppanel’ (meaning top skin(s) sections with stiffeners and other attached systems and structural materials).
From the photos you expect the panel tearing near the wing root and rotating up from that root with a ‘hinge’ line roughly running through the end of the second outer slat position. You can see an upward bent top panel edge, still attached to the‘outer’ wing, at that line.
On one of the photos taken from above you see a large top (black) section missing from the wing.
During the explosion you see the flames ‘following’ and ‘shielded by’ the dark object. Which I would not expect if it was an escape slide.
There is a photo of a large piece of flat panel lying topside down on the runway/taxiway area, with what may be yellow tape/hose draped round it. Striking that it is not covered in soot or burned.
B. Enginebreak away:
For this item the video material is incomplete. Of low quality and dynamic. And starts only when a crash situation was clear. But to try to figure out what happened ...with what we have ... the plane rotates around the right hand engine so to speak, after it broke away. This happened in such a manner that it cut fuellines and (partially) ruptured fuel tanks. With probably the fire running from the engine to that fuel pool. Fire in the engine is visible at the start of the break away video segments.
A+B =combining these two items:
If the initial fire started around the righthand engine, which was away from the centertank. And assuming that the center tanks content had been consumed first during the trip, giving them a more explosion prone gas/fuel mixture (at least compared to that of a fuel filled tank). Next, the fuel pool fire may have heated up that center tank volume from the outside, leading up to the explosion that we discussed under item A. This explosion (further) opening up the righthand center upper fuselage. Which would explain the fact that the right hand side fuselage shows far more damage than the left. While cargo holds appear to show minimal soot. And maybe also offer some explanation of why most slides were initially deployed on the right hand side at the start of the evacuation. And passengers later escaping via the left hand slide aft.
I am not familiar with the engine break away design scenario’s of the 777. But this case will surely be used to review them. I wonder if the sequence of events of this accident will turn out to be one of the 'foreseen' scenario's, either a design one or even a certification one.
Sorry for the long post.