Wouldn't the target therefore know that he was under fire, and consequently be unlikely to hold still in an exposed location for nearly 10 seconds?
Not necessarily. There was an earlier record, again by a Canadian IIRC, where the shooter was trying to hit a Taliban carrying a rocket launcher. Although bullets were striking around the target, he apparently never thought they'd hit him. And probably never knew they did.
There's an earlier anecdote, about Union General John Sedgwick. From Wikipedia:
Sedgwick fell at the beginning of the Battle of Spotsylvania Court House, on May 9, 1864. His corps was probing skirmish lines ahead of the left flank of Confederate defenses and he was directing artillery placements. Confederate sharpshooters were about 1,000 yards (900 m) away, and their shots caused members of his staff and artillerymen to duck for cover. Sedgwick strode around in the open and was quoted as saying, "What? Men dodging this way for single bullets? What will you do when they open fire along the whole line?" Although ashamed, his men continued to flinch and he said, "Why are you dodging like this? They couldn't hit an elephant at this distance." Reports that he never finished the sentence are apocryphal, although the line was among his last words. He was shot moments later under the left eye and fell down dead.
Charles McMoran Wilson, 1st Baron Moran, wrote a book titled "Anatomy of Courage," based on his experiences during the First World War. In it, he relates seeing a British officer walking in the open between trenches, while enemy machine-gun bullets were spattering all around. Walking, not running.
And finally, there's a famous quote attributed to none other than Winston Churchill: "Nothing in life is so exhilarating as to be shot at without result." (http://desertonfire.blogspot.com/2009/07/source-of-famous-churchill-quote.html)