Day 1

I've put few more marker to the map, Now you know that "corridor W" is save, have found a floor that collapsed in corridor N but don't see (yet) anything suspicious further. You know that that a part of floor is suspicious in the hall, it required a touch distance to make floor investigation as due to the dust the floor looks no different.
Angius, please explain where are you moving - where are you checking the ground with your hand made pole

Hey, I decided to do fast forward. Angius collapse some of the suspicious floors with his hand made pole. Working together you manage to go through the big hall and find all of the poor flooring - marked in pink on the map
You don't see any sharp spikes these pits, but they are of same 10 ft depth and the one Bellow almost fell into.

Angius - make me a DC 10 Sleight of Hand check. If you fail, your pole will collapse at a moment and few of your javelins will fall into the pit.

Anguis crush some of the fragile floors with this pole and looking how it works is too excited and fail to see that the ropes are too loose, so one javelin falls. He takes another and this time makes sure ropes are good every time before using and finishes the job.
The javelin lays on floor of one of the pits.

Walls are made of solid stone blocks (5 ft wide and 10 ft tall - the ceilings are also 10 ft). The blocks are not new and partially crumbled/cracked ... I mean they look like many centuries old.

Actually as you were working in the big hall you discovered some engraved pictures on the walls. Everyone roll me history check, your memories are still loose but you may remember some chunks of history from the books you have red (DC10) or even places you have visited (DC15).

Elrond and Bellow discover room B to be safe and so is the next room. More over it opens you a view to a corridor with a passage, but you as you touch and clean dust from the floor in that corridor you realise it starts with the the same trap as everywhere around.

Floor of the "long hall G" to the north is different. It is made of granite blocks of size a bit more than 1x1 foot. As you touch them to investigate if they are pressure plates you find them to be stable and not moving. They don't seem to break as well. You still struggle to enter. Non't you?!

Bellow, you have a strange feeling that you have been here. You have seen those paintings in a hall larger that this and remember an old Githzerai (race name) guiding you through Tombs full of traps, secret doors and powerful magic created to give time for Acolytes to flee the place and save the artefacts that are kept int those places. Those are no random goblin traps. The traps in this place should combine and complement each other to make it really hard for anyone without knowledge to pass through, but anyone with knowledge to flee.