After the limo passed him, all he had to do was cross Houston Street, which was easy from the side of the street that he was on. And then he was on Main, and he could have seen it all unfold on lower Elm.
So, there was no traffic on Houston, save for the slow-moving motorcade, and he was south of the motorcade. He wasn't going to get in their way. He just had to scoot across the street and go past the decorative wall, and now he's got a open view. And he had plenty of time because the motorcade traveled very slowly and then slowed down to a crawl. Many said it stopped completely.
He didn't even have to past the pergola. Even from the corner of Main and Houston, he could seen lower Elm just fine.
But, it would have been hard to do from the other side of Main. He'd have had a better view of JFK, but it would have been harder to cross the street. I bet that Dallas police didn't want people darting in-between cars in the motorcade. But, it would have been easy as pie from the side of Main he was on, the south side, because the motorcade was turning right, and he was left of it.
So, it was a very opportune spot.
That's Cruz. I don't think it would be wise for him to deny it.
Then again, he's going to have a problem if he admits it as well.