Looks to me as if John has a few MM left, if the pad is what I think it is in the picture. If, on the other hand, the pad is not showing and the gap represents the pad thickness, then you are probably due for pads. If the noise maker ("wear indicator") hasn't kicked in, John is not down to 1 mm. The wear indicator is pretty noisy.
From the service manual:
Using a ruler, measure the pad lining thickness.
12.0 mm (0.472 in.)
1.0 mm (0.039 in.)
If the pad lining thickness is equal to or less than the
minimum, replace the pad.
If the dealer says your pads are down to 2 mm and need replacing, ask to see. They have been known to mis-measure once you are out of warranty. Measure from the working surface to the metal. Do not buy into some service adviser story that the measurement is to some other place. If they are down to 2 mm and you are in the shop and you want to get your brakes done, fine. But if they are not down to 3 mm and they are telling you that they are below 2, then that tells you something.
You might be able to spot the wear indicator: https://www.youtube.com/watch?v=XRz7BDaSONM
(not a RAV4)
I enjoyed the video discussed here: Weirdest brake job video I've seen ...