Continuity mistake: Mary is touching Peter's face when her husband takes her away. She bends her arm to her chest, but in the following shot it's back next to Peter's neck and she is repeating the previous movement. (00:02:25)
Continuity mistake: When Gwen is giving her speech, in the background are two boats passing. In the next shot they disappear. (00:12:50)
Continuity mistake: When Stan Lee is in the audience of the school ceremony, in the close up somebody is on his left but in the open view that person is gone. (00:14:20)
Continuity mistake: When Aunt May is about to do the laundry she gives Peter a sandwich with a large piece of lettuce in it, but in the following shots the lettuce disappears. (00:26:40)
Continuity mistake: In the scene where the power is out and two planes are on a collision course with each other, the microphone of one of the air traffic controllers changes from a correct position facing his mouth, to an incorrect position hanging way down and away from his mouth, between shots.
Continuity mistake: When Gwen nearly falls off her own flats trying to avoid Oscorp's cartoon security, Peter grabs her. She clings to her and her mug hand is against his arm. She says "Hi!" in the next shot and her arm is lowered. (01:09:20)
Continuity mistake: Enraged because Spidey is being filmed by cameras, and he is not (best villain motivation ever), Electro sends a wave of electricity towards him. Spidey jumps over police car 7703 (the one that he dented landing spine-first in it earlier) but the slow-motion sequence that follows takes place featuring car 1206. (00:56:40)
Continuity mistake: When Electro approaches the cables in Times Square, in the overhead shot we see that the person closest to the grate he targets is standing one row away from it. The following shots are consistent with that, even if we can see that there are more people. When he opens the grate in another angle, that person is standing right next to it. And when he digs his hands into the cables, some person with khaki pants is walking across the metal grids, but he wasn't there before. (00:51:35)
Continuity mistake: After Gwen says "I'll be moving to England", she takes a breath, swallows, closes her mouth, but in the next shot her mouth is open. (00:50:40)
Continuity mistake: When Harry at the board meeting sarcastically paraphrases the Connors incident mentioning the "giant lizards" you can see Felicia Hardy in background is writing down things, but she isn't in the previous shot. (00:37:05)
Continuity mistake: At the board meeting, Harry is playing with his father's electronic seal in a way that displays towards the camera the side with the Oscorp logo. But there are two different camera angles from opposite sides, it can't be facing both at the same time. (00:36:55)
Continuity mistake: Gwen's phone call;Spidey holds the plutonium in a different position in each shot - at the end he even just has it standing perfectly vertical on its own. After the first two shots -when his arm goes from behind the grill to under his chin - we are not talking about consecutive shots anymore and the camera cuts away each time for over two seconds so it is technically possible he'd change position every time, but it randomly goes from above the grill, to behind, front, and perched on it. (00:11:25)
Continuity mistake: In the second part of the chase, Sytsevich drives off leaving all the police behind and all the plutonium falls from the rack except the second container from the left in the top row. During Spider-man's antics in the back of the truck you can see the container about to fall (and eventually falling) from the third hole from the left. (00:10:50)
Continuity mistake: Aleksei Sytsevich abruptly stops the truck creating a pile-up of police cars. There's a close-up of a container of plutonium falling off an otherwise full rack, but the following part of the scene shows the rack half empty, and in any case the one contained that fell in the close-up was the bottom left one, in the rest of the scene the one missing from that column is the top left one. (00:10:25)
Continuity mistake: When Spidey wastes 20 seconds of valuable time for the ever important task of fixing Max's combover, he says "Lick that", and in the next shot Max does not lick 'that', but 'the other one'; Spidey put in front of him his left hand but the reverse shot shows Jamie Foxx's tonguing Spidey's right phalanges. (00:10:00)
Continuity mistake: When Aleksei Sytsevich says his own name and cackles, we see the other marauders jumping on the Oscorp truck. There's a shot from a crossroad with a pedestrian wearing a grey suit that looks at the police car in pursuit, and at the street corner there's a woman by the garbage bin; the camera angle changes and the people at that corner have changed. (00:08:10)
Continuity mistake: When Mary and Richard Parker says goodbye to their son, the scene is similar but also different from the previous movie; she delivers her line with a calmer voice and doesn't stroke his hair in the jittery nervous way of the original. The dad's farewell to Peter is also longer and here they touch hands. (00:02:25)
Continuity mistake: When Peter looks at Gwen's mementos, the photo he had in hand and the USB key both change position between shots. (02:07:50)
Continuity mistake: Peter is absent-mindedly listening to the news while Aunt May is putting away some objects. There's a cut while the speaker says "return of the web-slinger" and May who just had put down some letters is suddenly lifting a book. (02:06:25)
Continuity mistake: The one kid Spidey helped is looking at the window during the news story about Rhino breaking out of prison. He leans forward, but he's in a different position between shots, and his wind turbine is powered up only in the last shot even if it was still two shots before. (02:06:15)
Answer: Peter could have webbed him up and called the police anonymously.
MasterOfAll
Very likely. However, there was a deleted scene in which Peter, out of anger over Gwen's death, almost beats Harry to death.
Yes. We also see Goblin getting knocked out when all hell breaks loose, and the gears all break apart. Chances are, Peter just webbed him up. (Although, as the other response says, he also got beaten up in a deleted scene.)
TedStixon