Deliberate mistake: In the parking lot at the horse track, the old cars are so huge, they don't fit properly in the tiny modern spaces. They are hanging over the backs of the spaces so badly that the drivers would only have about two feet to try and get their enormous cars out of the spaces.
Deliberate mistake: Look closely at the horse track parking lot. To fit more of the cool period cars in the shot, the director has the next row of cars parked in what should be the driving area between rows.
Chosen answer: Goodkat didn't say "hey, Slevin, I'm gonna shoot her here and here. Y'know, FYI." Slevin has been trained by Goodkat. Slevin knows where Goodkat is going to shoot Lindsey because that's where Goodkat always shoots people when he's assassinating them.