Can 'where' introduce a specific manner without an antecedent?

I came across this sentence when reading Eclipse, where Sam (werewolf) was the leader of the pack: “ Sam approached Carlisle where he stood in the front, the huge pack right on his tail.”

I’ve known where to be of tremendous and versatile use in attributive clauses where it functions to qualify or specify a more generic antecedent as in We used to do this thing where we would sneak under Alice’s bed and wait till it’s midnight to scream at her. In this sentence, the antecedent is the thing, where introduces an attributive clause to explain what that thing was.

But in Sam approached Carlisle where he stood in the front, the huge pack right on his tail., there is no apparent thing to which where can be attached to. So can where introduce a specific manner/approach/situation/etc. without there being a head noun?
And I assume ‘where he stood in the front, the huge pack right on his tail’ functions as an adverbial of manner as to how Sam approached Carlisle?