Piggy Piggy - S1-E6
Continuity mistake: The people that Tate murders at school have different wound patterns. Episode 5 they say what Tate did to them, episode 6 shows the attack. Episode 5 the goth girl says Tate asked her if she believed in God before shooting her - episode 6 he asked her nothing, instead just shot her. Episode 5, the guy in the letterman jacket illustrates his wound to be a single round to the head - episode 6 he shoots the letterman with a shotgun in the chest, not a handgun to the head. Episode 5 the cheerleader shows no apparent wounds of being shot - episode 6 Tate shoots her in the face with a shotgun.
Answer: He flew back a few times to be with her as mentioned in their fight.