Feature or Bug?

Trials of Chaos room 3: collect 3 soul cores and place in the altars.
After collecting one of them it starts adding a debuff which will kill me quickly at 100 corrupted blood. A rare monster is stood on top of the stone altar, and even though I press the prompt button that appears on the stone altar to get rid of the soul core, the animation refuses to happen because the monster is too big and in the way. I can't kill the monster quick enough before I die from the debuff, and even though I have the prompt to place the soul core, it kills me because it doesn't remove it from my character.

Obviously the answer is get stronger... but my question is should a monster be able to physically stop an animation when I have a clear prompt to place the soul core?