IMO every search engine wants the webmaster to do what is best for the searcher/visitor.
In an ideal world you would have a good amount of content text and a couple of external links towards "independant type" authorities/sources which are very much on theme/topic on more or less every content page of your site (take the example of a scientific publication).
Just linking to the top five in the serps does not mean that that link is necessarily most on topic/theme or most informative or the real source of information you are referring to.
If I were a search engine I would give extra points for an external link towards a "deeper" page for example. Most probably that link would be very on topic, or more on topic than an indexpage.
There are algorithms described in which a first ranking would occur for a search query, than a second one which looks how many of the "inner-crowd" (say the top 250) link towards your site to result in a re-ranking. (Do your peers vote for you as well). Do some reading on HITS - Kleinberg