In X-Factor #20 (by Peter David and Khoi Pham), Quicksilver used some stolen terrigen crystals form the Inhumans to give mutants their powers back and lied to them and claimed that the government caused their loss of powers (and that the X-Men and X-Factor were government stooges). It is a bit unclear what his end game, but when he was discovered to know the truth of how things happened, he stabbed one of the members of his group to get away (granted, she had just the previous issue stabbed Siryn)...
Rictor then took Quicksilver's crystals from him, and that destablized their returned powers, possibly killing them (they didn't actually die, but he didn't know that).
4. CAPTURED THE WEST COAST AVENGERS, TRIED TO KILL THEM
In West Coast Aveners #33-36 (by Steve Englehart, Al Milgrom and Joe Sinnott), the team is captured by a plot involving some Communists trying to get revenge on Hank Pym. Quicksilver turns out to be involved...
The whole thing is pretty haphazard, though, with Quicksilver's role in the story being constantly downplayed...
So while yeah, he clearly DID want to kill them, it was all so weak that I have it slightly higher on the overall list.
3. CAPTURED ALICIA STORM, PLANNED TO KILL HER
In Fantastic Four #304 (by Steve Englehart, John Buscema and Joe Sinnott), Quicksilver sure seems like he intends for Alicia Storm to die here, right?
He is leaving when the FF shows up, so it sure seems like he fully intended to leave her there to die, so that's not good.
Hot damn, Buscema's evil Quicksilver was AMAZING.
NOTE: This era of Quicksilver evilness was later retconned. I was planning to feature that in the future, but I should have tossed in a mention in the article that I was planning to spotlight the retcon later on. My bad! But yeah, so ixnay on the etconray talk until then.