A little training works wonders for the nerves when in a situation like that.
And he had guts.
The other guys were just pulling triggers. He was aiming and putting his bullets where they count; a thorough professional.
I recall from years ago there was a bank robbery with the robbers dressed to the nines with Kevlar protective gear (even a neck piece) and weilding assault rifles.
They did a TV re-enactment of the whole ordeal about a year later. In addition to going to a local gun store to beef up their supplies, the cops wisely hit the ground and took aim at the knees. They wisely used their brains and their training.
That’s not to say that it wasn’t a harrowing experience, but the cops prevailed even tho outgunned.