As far as springs flying across the room: they indeed do, and do so silently, like black death in the dead of night. With lenses, the problem is not (usually) as extreme, but, beware folks, if you do attempt to take apart any lens shorter than 28mm, you had better be absolutely positive of both the direction and the order of the elements that you remove from the rear. The 24s are amazingly complex and I could imagine how complex are the shorter still.
Many a time I have crawled on the floor and used my hand (or a damp rag), to scour that floor for a ball bearing that has lost its bearing. They ALWAYS, ALWAYS hide in places that never see the light of day. But, again, yes, the springs, especially the ones which hold that ball bearing (try the Pentax K mount, 2/50mm for new ventures of frustration) are amazingly potent in their trajectory. I have YET to learn after all these years to ALWAYS place a clean, white towel immediately underneath the work that I am doing. I keep telling myself "It's just one thing that I have to remove" and then all goes to H---!
One tip I can offer to those who will learn better than my obstinance allows is this: when taking the aperture ring off the lens body, place the whole lens in a food storage bag and then take off the ring. THEN, if the ball bearing and spring go flying, they will not go far because they will be captured within that bag. I say this but 'inconvenience' has yet to tether that logic to my damn brain.
One ends up having immense respect for camera technicians. The level of disclipline (and parallel satisfaction in finally getting the job done correctly), are profound. After literally decades of honing this work, I cannot yet call my self a camera repairman, but I can say, without equivocation, that I can clean internal elements as well as a 'clean room' can. I am left-handed: The secret, above all, (for me) is to wipe elements in a circular fashion after wetting them with glass cleaner, holding the element between the right thumb and index finger while holding a soft tissue with the left thumb and index finder and, again, with the right hand, turning that element disc around repeatedly. You MUST use a cleaner that contains a bit of soap, because using alsohol, alone, will set up static and dust will cling. The soap (only a bit) removes that static. - David Lyga