The thing is, guys can get into a rhythm and hit a ton out, but it was the sheer power on display that was so amazing. He was hitting drives 450-500 feet like it was nothing. It got to the point where even the end of that round was anti-climactic, let alone the next two. Given what that type of effort takes out of a hitter, I doubt he could have repeated the performance, but even if he did it would have been kind of pointless, and taken way too long. Everyone would've just been waiting to see him hit one out of the stadium entirely, which may have happened once in 80+ years.
When a first year guy, who almost threw his life away because of heroin, has perennial all-stars approaching him in awe because of what he did in the first round of an exhibition, they need to just hand him the trophy right there.