The dad decides to rest but stays with his kid as he plays games.
A stranger to the baby comes over and approaches the dad.
The father acts a safe base to his baby as they play together.
The dad leaves in order to get some drinks.
The parent is still present, but he is not playing with his kid as he did before.
The dad comes back and the stranger leaves to the bathroom.
The baby sees a person he doesn't know, so there's stranger anxiety.
The stranger and the dad are back in the room with the baby. He is still playing the game.
The baby is left alone with the stranger, so he starts crying due to separation anxiety from his father.
The baby is avoidant or dismissive of his father because he had left him alone with a stranger, and that caused him a lot of stress.
The baby is now fearful as the stranger is still present, and he is also scared that his dad will leave him as he did before. Therefore, even though his safe base (father) is present, the baby is still in fear of the stranger or that the dad may leave.