Continuity mistake: When they steal the truck at the mall they have to hot wire it to make it start. Later at the San Andreas fault scene where the road ends, in the same truck, he turns the truck off with the key.
Continuity mistake: When the Hoover Dam starts collapsing, we see that the side where Kim, the girl and Dr. Lawrence are goes off first, but in the next brief shot, the other side of the dam appears to go off first and then the trio's side.
Continuity mistake: When the helicopter is leaving the restaurant, one of the doors is ripped off. But in several shots, the door is back on. Then off, then back on.
Continuity mistake: The older brother cuts his leg on falling glass. The cut in one scene is on his inside left leg by the seam of his trousers, next scene the cut is on the top of his leg and the glass piece is a lot bigger.
Answer: You haven't missed anything. After the successful CPR, Blake is still wearing the two heart necklaces, but a considerable amount of time passes between then and when Ben gives them back to her, so we can presume that the necklaces had fallen off at some point in between. Since Blake had taken it upon herself to wear her sister's necklace with her own, the two chains could have been clasped together (which I've done myself), as if one.
Super Grover ★