Hmmm I think I could absolve every single one of those points with this..
First of all let me preface this as a fun debate since so many seem to have lost the notion and get heated rather easily. I just think it's fun ponder on making science fiction plots holes a possibility in that world.
The Alpha harnesses the power to reset time and if I remember correctly the death of an Alpha triggers the roll back to a predefined point of time.
If the notion of a time reset upon the event of an Alpha's death is acceptable then it's also acceptable that the death of a human, who has harnessed the Alpha's ability to reset time, can also reset time upon his death.
The ability doesn't necessarily need to activate through a conscious decision. Take hunting deer as an example; if you miss your shot and injure the animal then the adrenaline levels released by the animal actually spoil the meat, so the same levels of adrenaline in a human body could be the catalyst to trigger the ability.
The problem is that when time is reset he (Tom Cruise) retains the power to reset time, despite not having the Alphas blood (since he went back in time!)
The premise that you can go back in time, thus not being injured (or dead!), but still retaining your memories, and indeed your blood (!) is crazy.
And when he replays the day without killing the Alpha and dies, logically that should be the end of him. But no, the day still resets.
The premise that you can go back in time, thus not being injured (or dead!), but still retaining your memories, and indeed your blood (!) is crazy.
And when he replays the day without killing the Alpha and dies, logically that should be the end of him. But no, the day still resets.