While Thea is receiving chest compressions the EKG shows a flat-line. During actual CPR you won't see a flat-line, you see spikes during the compressions. You have to stop compressions before you can tell what the true EKG looks like. Same for a pulse. You will feel a pulse during compressions and have to stop before you can tell if they have regained a pulse on their own.
In Hong Kong, drivers drive on the left side of the road. In the scene where Oliver is chasing the Army transport, he is driving a left hand drive car on the right side of the street. It is very difficult for someone to register a left hand drive car in HK which means that it is highly unlikely that Oliver stole a LHD car to chase after the truck.
Even though no one told Ray Palmer the problem (Thea being near death), Felicity should know that his nanobots would be an alternative to Oliver capitulating to Ra's al Ghul.
Ra's says "Every man and woman in here have renounced their past life." "Every" is a singular noun; the correct sentence would be "Every man and woman in here *has* renounced his past life." (Using "their" as a gender-neutral pronoun is accepted in the 21st century, but Ra's generally does not use such modern constructs.)