Apart from the CRM aspect and general decision making, which is speculation until the "allowed elements" of the CVR are released, the rest is simple physics and energy management. With the flaps out forward trim for 12 seconds takes the trim well beyond the green arc, couple this with a reduction in the pitch power couple as thrust is reduced, the aircraft is only going one way... down.. increasing power after the aircraft tips forward or pulling back, as they did only deepens the dive... try it in the sim.. we just did..trimming back to a neutral position and then correct thrust management allows a recovery, but not from the altitude these guys had remaining.. doesn't matter if you look through HUD, FD or ski goggles its just a mistake, and we are all human..