The report I heard says there were no weapons involved. I'd like to think that if I was the courier, with my helmet on & visor down, carrying a relatively heavy box, and being confronted by an un-armed man, rather than give him the box of cash, I'd hit him with the box, before legging it into the bank.
Now, I've never been in this particular situation, so obviously I don't know how I'd actually react, and may just do as the guard did & hand it over, but I'd like to think that I'd have had a go.