Continuity mistake: Peter and Gwen are having a spontaneous reunion. Gwen tried her new laugh on Peter, and she's laughing at his positive reception of it saying "It's not adorable." Notice by her a dude with thin framed glasses and a beige jacket that walks past them. A few seconds later when she does the nose rub thingy, the same guy is again passing them by. (00:47:15)
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 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: A policeman spots the suspicious guy accessing the high voltage cables and screams "Get out of the way." There's a macroscopical continuity error here with an extra sporting a peach colored jacket that 'gets out of the way' twice in two separate shots and with completely different timing. (00:52:00)
Continuity mistake: After Electro launches Spidey against the police car, the huge dent on the door gets smaller between shots. (00:55:40)
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: Peter opens the closet and throws a red jacket on top of his dad's briefcase, then closes the closet. Several shots later, when he opens it again the red jacket is gone. (01:00:05 - 01:01:05)
Continuity mistake: When Peter is home watching the news, he grabs his cell phone and places his thumb on the screen. In the close-up it's away. This swaps back and forth. (01:00:35)
Continuity mistake: Watching the news after his confrontation with Electro, Spiderman picks up from the table the webbing device that got fried. He then throws it back on the table, where meanwhile all the tools shifted around randomly. (01:00:40)
Continuity mistake: Peter is in bed watching the closet with his dad's briefcase inside. He stands-up and his earplug falls out, but a shot later it's back in. (01:01:10)
Continuity mistake: Before Peter googles Roosevelt he drops stuff on the floor. The position of the objects changes drastically between shots. (01:01:20)
Continuity mistake: Peter inputs in Google "What is Roosevelt?" and gets as output for his search "Franklyn Roosevelt + New York" (01:01:25)
Continuity mistake: Harry just found by accident the secret interactive desktop from his father. He drags and drops a menu, but somehow when he checks out the item he highlighted, the menus themselves changed entirely showing stuff like "Max Dillon experiment" that were not there a moment before. (01:03:05)
Continuity mistake: Peter is cooped up in the garage window as he answers the phone after a night of dangerous experiments. First shot and his arms are free, close-up, and he's wrapped in a blanket. (01:05:00)
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: During the kiss in closet scene, Garfield has his hand on Emma Stone's face abruptly at the cut. Seconds later, when they concur that the kiss was "a bit rushed" they smile at each other with a completely different position - as you can see from the light rays on their faces. (01:10:55)
Continuity mistake: Peter comes back home and finds his aunt sitting on his bed staring at his serial killer-like collage. The two start talking, and during the conversation May has several locks of hair on or off the cheek as the two angles alternate. (01:16:45)
Continuity mistake: Harry wakes up to Spiderman's voice in his living room. He sits and looks at him. Notice the messy hair on his forehead. Changes shot (he is rubbing his nose like Gwen, just not as cute) and his hair is combed over properly. (01:20:50)
Continuity mistake: When Harry is talking to Spidey that barely camouflages his voice, the hair on his forehead keeps changing position between shots. (01:21:20)
Continuity mistake: Inside Oxford's North American office, Peter starts blathering; he says "Everything's a mess", he says; Emma Stone in the next shot has her hand raised. The mistake happens again at the end of the conversation when Peter goes "I'm sorry to bother you", and her raised hands go down her sides from the wide shot. (01:23:15)
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