i have a question

(SPOILER)from what i gathered, the reason voldermort couldn't kill harry (like, ever) is because a part of his soul is in him (harry). ignoring why voldermort can't commit suicide (unless you can explain that), he then gets in his head that the two wands are made from the same core. so he takes lucius' wand and that fails (beginning of HP7). he then tortures people to find out why, and where to get the elder wand (dumbledore).

the problem is, even though snape killed dumbledore, malfoy disarms dumbledore (iirc), after which harry disarms malfoy, thus making the elder wand his (harry's).

my question is: has anybody ever disarmed another person in the series? wouldn't that make those people's wands ineffective against the disarmer? and is this the case universally?