Visible crew/equipment: When Mr. Pink escapes from the cops and he's hit by a car, you can see the crew members in the background watching the scene.
Factual error: During the flashback of Mr. Pink escaping, he smashes a car window and the window shatters into several large pieces. Car windows are made of tempered glass, which shatters into hundreds of small pieces.
Plot hole: The cops are waiting for the robbers to arrive at the hideout after the robbery so they can bust Joe, and most certainly, they would have put surveillance on the warehouse. So why don't they intervene when Mr. Orange is presumably seen wounded outside of the hideout, or especially when a kidnapped cop is brought inside the warehouse? Cops aren't going to waste any time whatsoever letting one of their own be put in mortal danger, even over serious business.
Answer: It's a way of lighting a zippo lighter. If you snap your fingers close to it, your middle finger will strike the wheel and light it.
Nick N.