One of the reasons I've been a bit MIA from the blog lately is because I've been traveling a lot. On one flight, I noticed some interesting things in the safety manual. First, let's look at a section that isn't too bad:
This part shows a nice step-by-step for what to do in the event of increased cabin pressure: how to put on an oxygen mask. Note the "no smoking" sign to the side — smoking with one of those things would be bad. Here, the numbered panels may serve two purposes — it gives a reading order along the "z-path", left-to-right and down, and it also gives an order to the procedure. You need to follow these steps in order to put the mask on correctly.
Comparatively, this one from right below seems very strange:
If the numbers are meant to direct a stage-by-stage process (or even just an order for reading the panels), then perhaps I can paraphrase the overall meaning (and the signs to the side):
"In the event of either a land or water crash, first, African Americans need to cover their heads. Then, blond women need to grab their legs, followed by white men who should force their children down next to them into submission. Lastly, once all the other groups are safe, pregnant women should brace themselves. They're the bottom rung in our concerns."
Ok, so maybe I added a few minor embellishments, but my point should be clear: this sequence has no need of numbers for any purpose. Really, all people should brace themselves as quick as possible in one of these ways, not in any particular temporal order. And, despite that people probably would read it in a z-path anyhow, there isn't any need to read these in the numbered order here either.
I love this example especially because it provides great support for why sequential images are not always a sequence in time. Each of these panels simply shows a different viewpoint of a broader scene. It's a shift in Space but not in Time. Truly, you could rearrange these panels in any order and still maintain the same meaning — clearly a sign that no "time" passes across the panel boundaries.