In the person I mentioned, he needed a second to bring his arm down, take an arrow, and bring it up to the bow. Another second and a half to put the arrow on the bow, knock the arrow, pull back, and point towards the target. Another half a second for aiming. That's about three seconds worth, and you have to do that 10 times in a row with the following in mind:
o No fumbling when grabbing an arrow. Don't bother looking down when grabbing one or you will lose time.
o Smooth rhythm with minimal movement when bringing the arrow to the bow. If you're bending over and moving the bow to the side to put the arrow on, you're losing time. You have to grab the arrow at the nock and get it on the string in one movement while the hand holding the bow puts the arrow in place at the other end.
o You need to keep the bow pointed down range while you do the above so you have minimal correction when you pull the string. Note that this doesn't necessarily mean that your arm has to be fully extended the entire time.
o Instinctively pull the string to the same distance and anchor at the same point of your face. Your head needs to be at the same position so you can use two points of the arrow for aiming. Don't grasp the bow or you can affect trajectory when you fire. Don't pluck - keep your shooting hand anchored to your face. Don't stoop or lean unless you can do it exactly the same way each time. Any variation of your finger movement as you let go will cause the arrow to veer left or right. By the way, do all that in a half second.
o Don't marvel at the shot hitting the target. By the time it hits, you should already have grabbed the next arrow at its nock without looking.
o Again, minimal movement means less correction in stance.
o The quiver can be behind your back or on your belt - it's a personal preferece based on your style of pulling arrows and not a guaranteed advantage one way or another.
o The two riskiest points are the grabbing of the arrow and nocking it on the string. If you're not in complete rhythm, you can really fumble those up. On a 30 second speed round, your heart is racing and you really want speed, so your mind can play tricks on you and get ahead of yourself. This causes error in judgment and kills your pacing.