For those wondering what choices you must choose to get the secret route, here's the way, SPOILERS, obviously:
This begins when Arrow asks us, Wesley, if we are going to come along him, outside Dewhurst and into the Capitol. This is the timed choices between "I need more time" and "I can't." What you need to do is to NOT choose any of the choices and let the timer run.
Next, you are then given three set of choices after Wesley goes unconscious trying his best to help his bleeding father. You must choose accordingly: "Fine..." when he mentions about his dad's wellbeing to himself, "I don't know." when he asks if all of this was his fault, and "Focus on the past." when he asks how he can fix all of this.
That should do it. An unknown being will then ask us if this was what we wanted and hopes that we can find relief as we then play an imitation of what Wesley's life could have played out with the absence of the mysterious accident, a life that is now well beyond our reach.