When MacGyver yanks Paul out of Stone's restaurant, Soong and Lin are out on the streets looking for Paul before Stone notices he's missing.
When MacGyver goes back to where he had first seen Paul, he narrates, "Whatever Paul was into had something to do with this Wish Child business", but at this point MacGyver was not aware of anything to do with the Wish Child, only starting to find out in the next scene when Sam translates the symbol for him.
When Dr. Shan shows the stamp with the sign of the Wish Child to Mr. Lee, one can see that the Chinese signs on the stamp are not mirror-inverted as they were before, when the stamp was shown the first time.
If a watch crystal were powerful enough to work as a magnifying glass it would be useless as a watch crystal.