Dilan's senses were razor sharp and he could clearly detect the Vampires all around him. Their power was leaking and so was their bloodlust.
They had to unleash everything to heal from the injuries they had just sustained.
This was exactly what he and Sven had planned when they created the 'Rumbling', to lure the Vampires into a trap and kill them when they were at their weakest.
None of them could have known how bad Dilan's injuries would be after a skyscraper collapsed on him but that was a risk they took as it seemed worth it.
Dilan was fine being the bait, and facing dangerous situations because he was confident of surviving the catastrophe. Who else would be capable of increasing their Health stat close to 500 times stronger than the average human before the Primordial Ascension?
Nobody! Not while they were Tier-1 existences and shackled by the restrictions of being one.