My read for that was "a human could, reasonably, count one-by-one the number of engineers if they were all arrayed in front of them", while a human can't reason

My read for that was "a human could, reasonably, count one-by-one the number of engineers if they were all arrayed in front of them", while a human can't reasonable count "one, two, three" and get to a million. I would say that a number humans can reasonably count to is about ~15,000, maybe 25k, assuming you're limited to about 15 hours of counting. Any number over about 100k is simply a number humans are incapable of counting up to from one.