I got the strong impression that there was more contrived there (in-universe) than the simple matter of the troll catching Hermione when she was out. The amount of time that passes between Harry injecting her and Dumbledore’s arrival doesn’t seem to be long enough for the effects of the oxygenation to fail. (Will have to reread / research brain death to be sure I’m not jumping at shadows. It does seem that magic, at least, has concluded for sure that she’s dead, and Harry doesn’t seem likely to have time to save her even if magic is mistaken and she has a couple more minutes before her brain is irrepairably damaged (the time turner feats would be frankly badass if he could pull it off).) All of which leads me to believe that Quirrel (or whoever was behind it) took measures to make sure that there was no hope of saving her short of phoenix tears, unless they took precautions against even those, somehow.
Alternative explanation: Magic oxygenation shots don’t work because the inventors did not understand biology, just like the inventors of broomsticks did not understand physics.
Answer which doesn’t break established characters: A death eater disguised as Dumbledore lied.
Answer that I can think of that is the least bad: Quiirrelmort steals !Harry’s time-turner and comes back from 6PM to spill the soup and provide an alibi for how he suppressed the wards of Hogwarts (which have been established to detect sudden serious injury of a student- that’s why Malfoy had to die slowly), and used the troll to kill Hermione for the purpose of turning !Harry into the person who has the motivations required to complete the intended narrative.
I got the strong impression that there was more contrived there (in-universe) than the simple matter of the troll catching Hermione when she was out. The amount of time that passes between Harry injecting her and Dumbledore’s arrival doesn’t seem to be long enough for the effects of the oxygenation to fail. (Will have to reread / research brain death to be sure I’m not jumping at shadows. It does seem that magic, at least, has concluded for sure that she’s dead, and Harry doesn’t seem likely to have time to save her even if magic is mistaken and she has a couple more minutes before her brain is irrepairably damaged (the time turner feats would be frankly badass if he could pull it off).) All of which leads me to believe that Quirrel (or whoever was behind it) took measures to make sure that there was no hope of saving her short of phoenix tears, unless they took precautions against even those, somehow.
Alternative explanation: Magic oxygenation shots don’t work because the inventors did not understand biology, just like the inventors of broomsticks did not understand physics.
And yet the broomsticks work.
Easy answer: Dumbledore lied.
Answer which doesn’t break established characters: A death eater disguised as Dumbledore lied.
Answer that I can think of that is the least bad: Quiirrelmort steals !Harry’s time-turner and comes back from 6PM to spill the soup and provide an alibi for how he suppressed the wards of Hogwarts (which have been established to detect sudden serious injury of a student- that’s why Malfoy had to die slowly), and used the troll to kill Hermione for the purpose of turning !Harry into the person who has the motivations required to complete the intended narrative.
Dumbledore teleported by pheonix. I don’t think a disguised death eater could do that.
Yeah, that solution solves the immediate problem by introducing a much larger one.
-And Dumbledore arrives a couple of seconds too late.
Since he traveled there because he sensed her death, that’s neither surprising nor contrived.
DIdn’t Malfoy have to die slowly, because the wards on the castle detect serious injury?
I think that’s true, but I’d lean towards this discrepancy being a plot-point rather than a plot-hole.
They went over this, too.
Dumbledore may have had other things to do, possibly, as he may have needed to arm up or something.
Dumbledore spending too much time preparing before going to save a student is not one of his flaws.