Continuity mistake: When Archie's friends are gathered in Mary Margaret's apartment after the funeral, the cutlery in the bowls of salad moves around between shots when Ruby is talking. (00:12:50)
Continuity mistake: When Emma and Henry are having breakfast at Granny's Diner, the spoon in the empty cup next to Henry's plate (on his left) changes position between camera angles. In the same scene, Emma's right hand alternates between resting on the table, and picking at her food. (00:13:45)
Continuity mistake: At Lake Nostos, the pendant on one of Emma's necklaces alternates between being hidden behind her neck (under her jacket) and being visible on her chest. This is seen, for example, when Cora fails at ripping her heart out. (00:27:45)
Continuity mistake: During the battle at Lake Nostos, after Emma lunges at Hook and he flips her to the ground, the amount of dirt on her clothes repeatedly changes. (00:28:00)
Continuity mistake: After Regina places a rose on Cora's body, the position of the green leaves repeatedly changes between shots. (00:22:05)
Continuity mistake: When Emma is trapped inside the cell and is gripping the bars while talking to Hook, she's holding different bars between shots. This happens several times. (00:14:50)
Continuity mistake: Right before Emma and the other women get trapped inside the cell, Emma is reading the scroll left by Rumplestiltskin. The way she holds the paper keeps changing between shots. (00:13:40)
Continuity mistake: When Hook attempts to rip Cora's heart out, as he pulls his hook out of her chest, the hook is pointing downwards. In the next shot, it is pointed to the right. (00:12:55)
Continuity mistake: When Hook kills Regina's guards, the first guard can be seen collapsing. Cuts to an overhead shot, and he collapses again. (00:00:50)
Continuity mistake: When Anita lies dying, Red Riding Hood holds her hand over her mother's chest, in front of the arrow, and Anita grabs her hand. In the next shot, their hands are down at Anita's side, behind the arrow. (00:31:10)
Continuity mistake: In "That Still Small Voice", when Regina throws the piece of glass down the shaft, it lands on the rest of Snow White's glass coffin, which has several holes in it. When Emma finds the coffin in this episode, there is only a single hole in the glass, and the ends of the coffin (made of wood), are much smaller. (00:20:15)
The Heart is a Lonely Hunter - S1-E7
Continuity mistake: When Emma is with Graham at the Sheriff's office at the end of the episode, her hair keeps changing. For example, in some shots, there is a lock of hair hanging down the left side of her head. In others, it is tucked behind her ear. (00:36:15)
The Heart is a Lonely Hunter - S1-E7
Continuity mistake: When Emma is pressing an ice pack to the wound that Regina gave her, her bracelets repeatedly move up/down her arm between shots. (00:36:25)
Continuity mistake: In the scene where Albert Spencer burns Jefferson's hat, Ruby's hair alternates between hanging down the side of her face and being tucked behind her ear. (00:35:25)
Continuity mistake: When Hook has climbed down the Beanstalk and is greeted by Cora in the rain, the wet hair plastered to his forehead changes throughout the scene. (00:00:30)
Continuity mistake: When Albert Spencer confronts David at Granny's, Henry's coffee cup moves to a different part of the table, and back again, between shots. (00:04:40)
The Doctor - S2-E5
Continuity mistake: When Regina is in the stable with Daniel, after she says "No, I won't lose you again", in some shot, she has her hands on his face/neck. In others, her hands are on his shoulders. (00:31:45)
The Doctor - S2-E5
Continuity mistake: When Hook is tied to the tree, the arrangement of the ropes changes throughout the scene. (00:24:40)
The Doctor - S2-E5
Continuity mistake: When the women find Hook under a pile of dead refugees, the amount and position of the dirt on his face changes a couple of times. The scarf around his neck also changes position. (00:01:40)
Continuity mistake: At the beginning of the episode, when Emma and Mary Margaret are walking through the camp with a group of refugees, in the first shot, they're at the edge of the camp. Cuts to a different shot, and the group have moved to a different part of the camp and are situated next to a table, before they walk over to a shed. In the next shot, they are farther away from the shed. When it cuts, they are standing next to it again. (00:05:00)
Answer: He knows who she is because he knows that the fairy tales are true. He was also shown to sneak out to go see Emma or someone else. Sometimes he succeeded, sometimes he didn't. This is how he knew to look for her despite his strict mother.