ETA, Lindsay's story from oceanup:
From Linday: '@ NIU in Dekalb. They were filming a scene where they shot many gun shots. Also, we got to watch as they used their effects to make it seem as if the glass was being shattered by the gun! Last night they filmed at an auto parts place in Dekalb from about 7 PM to 3 AM.
They pretty much filmed the same scene over and over again, which was Zac's character, his love interest and another actor. When they were done Zac came out and met the fans who waited for him and he was so nice! He did not seem angry at all to be there, and he was so genuine! I've heard from a very reliable source that their done shooting and leaving DeKalb by the end of this week! :)'
It looks like he went back to The Junction after all and per twitter apparently it was to do a reshoot:
Based on twitters it sounds like he later went to Lee's Auto Parts to film the scene where he breaks in and steals parts:
Also I wanted to post some other pics of Speedway filming from FB not directly including Zac, just in case people wanted to check it out. I posted them as thumbnails, but click on each to see a large version if you are interested.