Had to load an earlier save [SPOILER(S)]

[dunno]

First of all, I couldn't even come close to describe how much I like
Overture & Black Plague.. So I wouldn't even try ^^
Then they manage to surpass them with Amnesia..
So veery f*cking huge thumbs up to you guys at Frictional Games!!

Anyway,

Spoiler below!

I just got out from Choir, when those red organic things started
to appear, and rocks blocked the way both to Choir and Transept.
I messed around for like 10-20 minutes or so, but I didn't have the
slightest idea where to get the vitae for saving Agrippa (I got the other
2 ingredients).

When I was running out of patience, I loaded my way back to Transept,
where I found out what I've missed. -I didn't pay enough attention to the
bars on the floor and the hole under them where the victim's blood was
drained.

That was the only part where I stuck, so I don't think that this possibility
was intentionally made.

Just wanted to point that out..