Azarak would have hardly flinched from the sudden burst of liquids launched at him when he regained his footing within the room, had he been in his demonic form. 

But he wasn’t.

With the restrictive human body his only tool for the job, fragile and pathetic as it may be, he had to rely on speed and manoeuvrability rather than a dogged power and durability. Hence, relying on the fact that the fastenings for his jacket had broken sometime earlier in the night, he shrugged the restrictive clothing off and threw it into the path of what he had no way of knowing was acid. It was a close cut thing, and even as he moved away from its path (assuming realistically that the material may not stop his opponent’s acid, nor what he briefly saw was a follow up charge) he skirted rightwards and further into the building. The acid cut through the jacket but it didn't find any purchase on the demon himself, nimble as his dodge was. It had also put him further away from his opponent’s intended target, possibly allowing Azarak the chance to level his pistol at the rapidly approaching quarry. 

Blood dripped down his spine... staining his pure white shirt, determination set upon his face.