So Searle's argument is correct after all. You are essentially saying that something can be one thing at a low speed, and a qualitatively different thing at fast speed. Such things certainly are possible, not just with respect to time, but with repect to other physical dimensions, such as temperature. Phase transitions are examples. It simply points out that, based on the kinds of things we already know and have no reasons to doubt, it is overwhelmingly unlikely that memorizing and executing a bunch of meaningless sguiggle-operation rules will generate either a conscious understanding of Chinese in the mind of Searle, or a second mind in Searle's head, that consciously understands the Chinese while Searle does not.
Someone can be really slow, taking minutes, hours, or even years to twig on something.
If someone could produce an extremely slow plane that crept along so gradually that it was virtually standing still most of the time, like a helicopter, it would still be flying. So, yes, there is a potential issue about timing, but this image does not quite capture it.