Lucivar was too emotional in dealing with this situation.
He was too angry, and spiteful at the prospect of death when he finally obtained, and tasted the tusk of power. Now that he knew what it felt like, he could not help—but anticipate other pleasing sensations when he achieved what he set out to achieve.
Dying an early death was out of the picture.
But now that Loki showed him what to expect, he realized that this wasn't a bad thing at all.
Albeit risking his death, he would gain the power of a God.
People gambled with their lives for less so this is an entirely win-win situation for Lucivar.
Not to mention, he needed this power to punch karma in the guts.
Only by having immense power would he be able to achieve that, and his bloodline is key.
"It was my mistake, I apologize for my brazenness," Lucivar apologized.
He was man enough to admit his mistake, Loki was simply helping him in becoming stronger.