Continuity mistake: In the scene where Captain Lennox pulls Mikaela from Sam after he has been blown away, you see her lying on the sand with the right side of her bra cup exposed but when you see her again her top is in the right position. (02:12:40)
Continuity mistake: When Lennox is trying to revive Sam, there is a close-up of the sock starting to slip out of Sam's grasp, but it's still in his hand. Then when the medics are using the paddles on Sam, clearly there is nothing in his bandaged hand. The problem is that there is another close-up of Sam's hand, after Mikaela professes her love, and the sock is still there in Sam's hand before it dramatically falls (it's the same close-up angle as the previous shot). (02:13:40)
Continuity mistake: When Jetfire says ''A living Prime! I don't believe it!'', he is leaning on a blue wall. When The fallen arrives moments later to steal the Matrix, Jetfire is nowhere near the wall, while at the rate he is crawling, it would take some considerable time to cover any distance. (02:16:34)
Continuity mistake: Just after Jetfire sacrifices himself, Ratchet orders Jolt to electrify, and we see Sam and Mikaela standing near Ratchet, but in the next shot when the Transformer's parts are flying towards Optimus, Sam is now a couple of feet away helping Mikaela stand up again. (02:18:16)
Continuity mistake: Optimus knocks over Megatron, and collides with the Fallen, knocking him off of the pyramid. But in the next shot where Optimus blows up the machine with a single shot, the Fallen is nowhere to be seen, and in the shot directly afterwards, he is right below Optimus. (02:19:06)
Continuity mistake: At the end, in the first aerial shot of the aircraft carrier, only a huge number '7' is imprinted on deck, but after the close-up of Mikaela and Leo there is also a huge number '4' imprinted on deck beside the '7', that is seen as Optimus and Sam stand beside one another. (02:21:25)
Continuity mistake: At the end of the movie, the first shot of Sam and Optimus shows them standing on the deck of CVN 71 (pan in), yet after their conversation they are standing on the deck of CVN 74. (02:22:00 - 02:22:38)
Continuity mistake: When Mikaela and Leo are in the silver Saturn, as Sam is hanging onto the passenger door, the rearview mirror is broken and hangs from the windshield, but is then intact once again.
Continuity mistake: When Lennox is demoted his rank is ripped from his shirt, but when he turns around his rank is back where it was originally.
Continuity mistake: In the scene where Sam is on the phone and explaining his hallucinations in college, he drops his papers on the stairs and there is a man that passes him. When they change the shot, the man is behind him again walking from the top of the stairs.
Continuity mistake: The multiple shots of the sinking Aircraft carrier are primarily shots of the CVN 74 (USS John C. Stennis) but also have shots of the CVN 72 (USS Abraham Lincoln) and the CVN 71 (USS Theodore Roosevelt). It is reported later on the news as the Roosevelt, and the Stennis is seen towards the end of the movie perfectly fine and providing air support.
Continuity mistake: When Mikaela's car is carried by a Decepticon helicopter, they are dropped in the building and there's a shot showing the airbags activating, but in the following shots (when the car stops moving or when they are getting out) the airbags are nowhere to be seen.
Continuity mistake: When Mikaela is talking to Sam on the phone after Sam had his "nervous breakdown", when he is picking up the dropped papers, the people on the right coming down the stairs come down twice.
Continuity mistake: During the shot where Mikaela runs into the lamp post, both the Pretender and the front bumper slide under the car as she backs up and drives forward again. Seconds later, as the camera angle changes and they drive away, the front bumper is re-attached with only a dent where it hit the post.
Continuity mistake: During the scene establishing the Decepticons on the Bayos freight ship, vehicles change. The first shot, overhead, shows Long Haul (green dump truck), MixMaster (grey cement truck), Rampage (red bulldozer), and Scrapper (yellow front loader with wheels). The next shot shows Rampage as being yellow, and Scrapper is now some yellow Volvo vehicle with treads and a claw. Also, by the angle of this shot and based on the previous shot, there would not be an angle to see through the background vehicles. In the next shot, when the transformers jump overboard, Rampage is red again, and the Volvo with treads is now the front loader Scrapper again.
Continuity mistake: After the Astronomy class, when Sam is in his dorm room he begins writing a green symbol on the Bad Boys poster, but when Leo and Alice show up that first green symbol has completely changed its shape and its position on the poster.
Continuity mistake: When The Fallen decrees that the Decepticons will now make their presence known, one of them knocks the flagpole off the top of the eastern tower of the Brooklyn Bridge. A short time later, another shot of the tower shows the flagpole is back and there is no damage.
Continuity mistake: When Megatron heads toward the tower in jet mode, he transforms and seen upside-down front flipping towards the tower before he lands. About a split second when he lands, he faces the other way instead of facing the tower.
Continuity mistake: When Leo, Mikaela and Sam arrive at Simmons's deli in Brooklyn, note the clock hanging on the wall behind the counter. Between shots the time changes from 10:20 to 11:40 to 1:05.
Continuity mistake: Optimus Prime kills Grindor by ripping it's face apart, after which Grindor falls over. But when Megatron kills Optimus, Grindor is gone. A huge robot like that would most definitley be seen in the wide shot with Megatron and Prime.
Answer: After the tomb, he doesn't appear onscreen again. There's no indication as to what happened to him.
JAGwire