Henry Gale is shot through the chest with an arrow. In at least one scene showing the arrow through his body, the back of the arrow is clearly pointing in a different direction from the front of the arrow, indicating that it's actually two separate pieces attached to the actor's torso.
Once the timer reaches 10 in the hatch, the beeping noises that indicate that time is running out run in sync with the countdown. However, in this episode a shot of the timer on 10 can be seen, followed by 13 beeps as the camera moves away from the timer. When the camera moves back, the timer is on 2.