Factual error: In Sam's premonition, when Isaac is still in the bus when it is falling down to the water, he is at the front of the bus. In reality the falling force should be pushing him to the back of the bus.
Factual error: Olivia's death starts with her laser eye surgery going wrong. Why did she only have one doctor with her, and then he left her alone? In any sort of surgery, especially ones with expensive machinery she wouldn't have been left on her own, nor would the doctor be working on his own.