ADVANCE WARNING: This is going to look like LitCrit. Read on; it arrives in the end at linguistic issues.
Affable Geek asserts your two alternatives are “different sides of the same coin”, and FumbleFingers “cannot see the distinction”.
I cannot agree. I think the ambiguity you discern is real, and the conflation of the two senses is possible only by treating the text improperly as a production of the “author” rather than a production of the character. (I put “author” in quotes because I mean by that not JKR herself, who is outside the text and not directly involved in the matter at hand, but the narrating persona within the text, the “authorial voice“.)
In the parsing of dramatic texts this is a constant and occasionally bitter battle between Literary Critics on the one hand and theatre people on the other. Literary Critics blithely assert the presence of “ambiguity” and “polysemy” in the author’s text, which is very impressive. But actors are not permitted the luxury of demonstrating their literary sensibilities. The actor has to decide what his character means: at every instant he is on stage he must commit himself unqualifiedly to a specific action and a specific linereading—and live with the result. We call it “making choices”, and it is often difficult and painful.
I suggest that the same decorum∗ governs the interpretation of dialogue in novels. With dialogue the “author”, who is capable of sophisticated polysemy, yields the stage to the character, who ordinarily is not. As reader you, like the actor, have to decide what Hagrid means.
- Are the came in came back and the came in came outta the same came, with the outta kinda trances providing additional qualification? —Some of them came back to our side from trances.
- Or are they two different cames? —one designating a change of affiliation and the other designating a change of consciousness.
Two different readings—for the actor, two different linereadings, with different stresses and prosody.
I have a preference for one of these readings; but I’m not going to share it, because I can‘t read the novel for you, any more than I can play a role you are cast in, and even if I could it would spoil your fun. But I’ll offer you this to build in to your thinking.
This ambiguity is occasioned by the fact that what is in play here is a verb, GO, with very low semantic content. It’s not exactly a light verb, but it’s something analogous: it doesn’t mean much of anything until you a)add prepositions and b)put it in a specific context. (JKR might have used a ‘heavier’ verb like emerge to avoid ambiguity, but she didn’t—given a choice between clarity and decorum, she always comes down on the side of decorum.) So: do we have the same verb, [keɪm], twice, or two different verbs, ['keɪmˌbæk] and ['keɪˌmaʊtə]?
∗ Here not “polite behavior” but a technical term signifying coherence and consistency of a dramatic character.