If the aircraft reached 150 feet in the bounce and the attempted goaround then the PNF was probably justified in calling "positive rate". One of the characteristics of the 777 is that although the landing flare is done with only one hand the rotate and goaround manoeuvre is done with both hands. Anyone who has seen lots of go-arounds on a 777 simulator will note the handling pilot gives a quick push on the TOGA switches and then pulls up to 15 degrees using both hands and looks at the PFD. The thrust levers then (should) go forward on their own. In the olden days the good old flight engineer made sure they did. These days the P2 very rarely backs them up. In the accident situation the non handling pilot was probably bringing the flap in to 20 and calling positive climb and raising the gear and then looking for the FMA indications and then wondering what was happening. Pitch and power saves the day however looking for and calling out the FMAs uses up valuable time, especially if you have not got the FMAs you are expecting (Thrust Toga Toga) The Asiana accident and now probably this one involved manual flying and an expectation of autothrottle to provide the required thrust.