Continuity mistake: The pseudo-UPS guy has a hand truck he leaves by the elevator, but when the baby is crawling with the camera inside the elevator cabin, the cart is by the door of the old bat instead. (00:28:05)
Continuity mistake: A pigeon coos outside the window when Baby Boo is at page 10 of the book. The baby actor turns a few pages bunched together, but in close-up he goes perfectly from 9-10 to 11-12. (00:23:00)
Continuity mistake: As Veeko tests the milk's temperature on Joe Pantoliano's bald head, the baby's hand position is out of continuity in the close-up compared to the shots before and after (off/on chest). (01:16:50)
Continuity mistake: Norby brings the baby to the bedroom as per Eddie's orders. We see him walk past the door holding a plush toy in his hand. When we see him in the room, the toy is under his armpit. (00:17:45)
Continuity mistake: In the overhead shot of the baby in the middle of the road in front of the zoo, the road is lit evenly, while in the shot just before you could see half a lane being in full sunlight. (00:42:55)
Continuity mistake: The three kidnappers run after the baby who got into the zoo; they jump over the shrub between two benches, but the leftmost bench is occupied by a lady who disappears between shots. (00:44:20)
Continuity mistake: When the nanny leaves the room, Joe Mantegna is holding the book in his left and pointing with his right hand, only to be shown holding the book in both hands in the following shot. (00:13:10)
Continuity mistake: The two associates sit Eddie on the bench at the bus stop; the mess all over Joe Mantegna's hair (in particular the green goo on his forehead) changes between shots. (00:29:35)
Continuity mistake: The first time we see Bink crawling out of the big lady's bag, in frame you can see Veeko's legs, feet up, but he has not been knocked out yet. (00:33:40)
Continuity mistake: Veeko spits his thumbnail in the same shot as he bites it, but then is still chewing it, and spitting it (with a sound as it 'lands'!) later. (00:24:15)
Answer: It might have taken a while for them to find the keys to the crane as well as figuring out how to operate it. Once they did, they could get him down.