its after Thorin chops off Azogs arm and immediately after he leads the dwarf charge. looks like Bolg gets hacked in the back by two dwarves. he even takes a knee. Looks like Dwalin did it.
Bolg gets messed up pretty bad in the battle and the ornaments on his face are used to stitch his face? If Dwalin hacked him up, then most definitely there will be some tension between the two of them when Bolg comes in the movies.
Though no idea whey they never mentioned him as being Bolg, despite their introducing other characters who would would not appear again until Film 2, like Thranduil and the Necromancer.
Did he look any different to the images we've seen of him so far? Did he still have the crazy hair and beard and the metal plating on his face? I originally thought one of the orcs who pulling Azog back into Moria was meant to be a younger Bolg. Seems very unlikely now.
On a somewhat related note I had a dream last night that Bolg was after me. Proper scary stuff.
Conan Stevens was original cast as Azog, right? So this "Bolg" he's now playing was originally going to be a resurrected Azog, alive and well in Dol Guldur...
When they split to 3 films, and introduced the Moria flashback they decided they needed a new Azog - first thought was to use the Orc played by John Rawls but realized the design of Yazneg was too generic and then brought in Manu Bennett to play a CGI Pale Orc.