I think this setting has two meanings:
First, from the big picture, the plan requires agents with both physical strength and IQ to complete various difficult tasks, but people with these abilities are often difficult to control. Therefore, it is necessary to develop drugs and cultivate these talents through acquired means.
Second, Uncle Shi said that he had seen people who had stopped taking the drug, their intelligence decreased significantly, and their response was slow. If Uncle has the sequelae after stopping the drug, let alone fleeing, even the basic survival is at risk, so he must find a doctor and find a way to get the drug. Otherwise, he doesn't have any special feelings for Rachel, why would he desperately run away with this crazy woman? ?
In fact, drugs are the clues that run through the whole drama, and the need for extra intelligence to enter the plan is also an important reminder for the follow-up plot.
Although many people compare Uncle with Bourne (note, it is Bourne, not Matt), they say that Uncle is mentally retarded and needs extra points to pass the test, and that Uncle still has the habit of holding sheep with his hands and so on. In fact, this part is still necessary. After all, no one knows how Bourne developed into the kind of person who jumped over the wall and reacted sharply.
The above is purely personal opinion, and it seems that there is no logical relationship, just a little thought.
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