Continuity mistake: In the astronomy class, Sam writes many symbols on the chalk board. In the first shot of the full board, one symbol is very messy. In a later shot, it is significantly cleaned up. (00:45:00)
Continuity mistake: In Astronomy 101, after Sam has written the symbols on the board, one symbol actually vanishes just after his professor's first close-up, and then reappears after the professor says, "I will not be punked in front of the dean." (00:45:10)
Continuity mistake: When Sam phones Mikaela after missing their webchat date he drops his books and papers, and one book falls upright on the top stair in front of him, which promptly vanishes and then reappears as the last book he picks up. All the books and papers keep changing in his arms between shots as well. (00:46:30)
Continuity mistake: While Mikaela and Sam are on the phone with each other (after the failed webchat date the night before), when Wheelie starts reaching up for the safe's combination lock in the first shot, there are no mouse traps on the floor near the short stool to his left, nor are there any cigar boxes. However, in the next shot two mouse traps (a snap trap with cheese bait and a glue trap) and two cigar boxes have all suddenly appeared. Wheelie proceeds to step on the two traps and then stands on the two boxes to reach the combination lock. (00:47:05)
Continuity mistake: In the scene after Sam starts writing on his dorm room's walls, the autobots are driving down the highway. We can see Optimus, Bumblebee, the twins, Ironhide, and Sideswipe. But in the next shot we can see Jolt between one of the twins and Sideswipe, only to be gone in the shot right after. (00:49:10)
Continuity mistake: When Alice and Leo walk in on Sam in the symbol filled dorm room, on the wall at the head of Sam's bed are three small-to-medium sized framed photos of Sam and Mikaela hanging vertically. After Alice pushes Leo out of the room, the frames change. Now there are two large and medium frames hanging vertically and another medium frame hanging horizontally. (00:50:00)
Continuity mistake: When Leo and Alice walk in on Sam in the symbol filled dorm room, there are large yellow symbols on the closet door which are partially erased when he knocks over the microwave, then back to the way it was originally. (00:50:00)
Continuity mistake: When Sam rushes back to his dorm room, he paints the first symbol on the Bad Boys poster, then rips the top poster off the wall and paints large symbols on the wall in its place. That poster remains gone in all the following shots except for two, where it is back on the wall above the Bad Boys poster. First when Sam knocks over the microwave and then when Alice fully transforms on Sam's bed. (00:50:10)
Continuity mistake: When Alice and Leo walk in on Sam's symbol filled dorm room, certain posters either suddenly appear on the wall, or vanish, or reappear ripped, between shots. (00:50:10)
Continuity mistake: In Sam's dorm room, there is a white mini fridge at the foot of his bed, flat against the wall under the Cloverfield poster. However, when Sam rushes after Mikaela just as Alice's 'tongue' grabs hold of his neck, that fridge has moved to in front of the closet door, but it moves back to its original position thereafter. (00:50:35 - 00:51:30)
Continuity mistake: When Alice is with Sam in the symbol filled dorm room, there is a large, twin, folding picture frame beside the bed, whose position changes from the right side to the left side of the windowsill, repeatedly. (00:51:20)
Continuity mistake: After Mikaela walks in on Sam and Alice, then leaves, Alice grabs hold of Sam's neck, and during his struggle the tall black floor lamp falls over toward the fridge, but that lamp is back upright thereafter. (00:51:40)
Continuity mistake: When Alice is kissing Sam on the bed there is a fan in the window beside the Bad Boys poster. It is there when she grabs him with her 'tongue'. When Mikaela returns and throws the metal box, it just breaks glass in that window frame, and we see the fan is suddenly sitting on the bed leaning against the Bad Boys poster, to the left of the window. (00:51:45)
Continuity mistake: After Mikaela throws the metal box at Alice and breaks the window, when Sam runs out of his dorm room screaming we see (and have seen multiple times prior to this) the wall and bathroom door opposite his door. Oddly enough, in the next shot from the hallway, Sam, Mikaela and Leo are actually leaving from a door that's farther down the hallway. Sam's actual door is the first one on the right, opposite the bathroom door - there is a bike wheel leaning against the wall beside the bathroom door. (00:52:00)
Continuity mistake: Mikaela is wearing high heels when she reaches the stairs, before entering the library. Then in the library, her high heels have vanished and she is suddenly wearing flat shoes in this scene. (00:53:50)
Continuity mistake: When Mikaela, Sam and Leo get into the Saturn there are no headrests on Sam's and Mikaela's seats, but when they kill the Pretender and are driving away, the headrests are suddenly there. (00:54:00 - 00:54:55)
Continuity mistake: The Saturn that Mikaela is driving has a moonroof that encompasses most of the roof, over the front and back seats. When the Decepticon Grindor captures them, in the interior shot looking up at Leo as Grindor seizes the Saturn, the car has a solid roof over Leo, which is also seen in the interior shot as they fall. (00:54:05 - 00:55:05)
Continuity mistake: When Mikaela deliberately rams the Saturn into the pole, in the front shot both headlights are perfectly intact after the impact, but in following shots the car's left headlight is gone. (00:54:40)
Continuity mistake: When Grindor seizes the Saturn, Sam falls out of the door and in Mikaela's close-up Leo's arm hangs out of the rolled down back window, but in the next shot that window is rolled all the way up, only to be rolled down again in following shots. (00:55:10)
Continuity mistake: When the Saturn has been dropped by Grindor, as the car falls with Mikaela, Sam and Leo inside, just before they crash land in the last interior shot, Mikaela's and Sam's headrests have vanished, and a large sticker has also suddenly appeared on Sam's visor in this shot. The headrests reappear when they are upside down. (00:55:35)
Answer: After the tomb, he doesn't appear onscreen again. There's no indication as to what happened to him.
JAGwire