With regards to stalling. The F/O (PIC) beleived they were going too fast, and losing height, and hence started pulling back. No-one can be sure why he continued to hold the pull back once the stall warner went off. It is possible that the 2 more experience pilots were not aware that the F/O was continuing to pull back on the stick.
Not sure which bits were right in the programme, it said that the RH seat pilot continued to hold full up - with the correct take over procedure this would not matter, the other pilot presses a priority button (and the programme showed the priority left light illuminated), this locks out the other side stick (though there are ways of taking it back) making the fact that the RH seat pilot was holding full up irrelevant, so either the correct takeover technique was used and the LH pilot did not take stall recovery action or he did not use the correct method and the two sets of controls would have resulted in the control inputs being put together to give a combined input and the full up stick on the RH side VERY important.