Oliver says that he found out that Green Arrow told him that Laurel was Black Canary. However, in Canary Cry (2016) he announced at Laurel's funeral that Laurel told him herself before she died.
At 11:21, Doctor treating Black Siren aka Laurel Lance tells Dinah "in a world where a man can run faster than light". No man or device can theoretically run faster than light. If she was referring to Flash, he runs faster than sound, many times so, but surely nowhere faster than or nearing the speed of light.
When Thea is in the room with Roy and more police arrives, Oliver forcibly takes Thea out of the room, saying that the police would have killed both of them (Thea and Roy). A few seconds later, Oliver says that they would not kill Roy because they need him alive to testify against Oliver. That is the fastest U-turn in the series.
While Jean Loring is correct that evidence deemed to be "fruit of the poisonous tree" is inadmissible, she is wrong to assert that evidence obtained and released by a criminal in the course of committing a crime is automatically illegal. As long as there was no police misconduct in obtaining the evidence it is legal. By way of analogy, if the police arrest a burglar for robbing your house and recover a gun belonging to you that was used in a murder, that gun is admissible against you on a murder charge.