Hmmm, I guess that as an engineer I expect the battery to fit flush and therefore had no problem shoving it in all the way but I can see someone being scared of pushing it past the threshold where the battery latch engage.
I wouldn't do the lift the catch method he first demonstrated, I would slam that blighter home DJI Phantom style as batteries falling out of Phantoms are always all over forums when a model is first launched. If you don't hear a good clunk don't fly it.
STEP 3: INSTALLING THE FLIGHT BATTERIES Push the battery into the battery compartment with the Yuneec logo facing upwards until hearing a 'click', which means the battery is installed successfully.