What did Tris sees during her Aptitude test?

Tori hands Beatrice a vial of clear liquid and tells her to drink.

A moment passes, and Beatrice stands in the school cafeteria, in front of a table on which are two baskets. One basket holds a chunk of cheese, the other a long knife. A woman's voice tells her she must choose one, but she refuses, and suddenly the baskets disappear and a massive dog starts prowling at her, teeth bared, and she realizes why she would've needed one of the objects. Beatrice remembers everything she knows about dogs and sinks down to the ground and lies down, hoping this will serve as a sign of submission. It does, and the dog begins to lick her affectionately.

Suddenly a child appears and runs for the dog, and it seems as if the dog is about to attack her when Beatrice decides to throw herself on top of the dog and wrap her arms around its neck to prevent this from happening. The dog and child suddenly disappear.

Beatrice finds herself on a bus, with all the seats taken. A man with a newspaper speaks to her, pointing to a headline reading "Brutal Murderer Finally Apprehended" and asking her if she knows the man in the photo. Though she vaguely recognizes him, she feels that something bad will happen to her if she says so, so she continuously denies that she's ever seen him before, despite the man's insistence that she's lying.

Beatrice wakes with a feeling of guilt, and realizes she is back in the testing room with Tori.