Help needed in Episode 5 Sequence 3 (Spoiler)

[Tideon]

I am stuck for the past two hours on this Museum Monster. I can not find any clue on what to do after he's been shot 3 times with a fire bullet in his fissures.

So after shooting him 3 times, his shoulders and stomach area stop glowing.. but then what?

Any help on this subject is very much appreciated.

[deadrabbit]

Go to the corners of the room and stock up on bullets and empty plastic bottles.
Hide behind the pillar and prepare your gun and bottle.
Sidestep out and throw the bottle at him and shoot to damage him.
You will know when he is damaged as he starts getting surrounded by black 'ink'
Hide behind the pillar which is glowing with a white rune on the floor now.
Repeat until dead (about four or five hits)