Portho finds the button as a routine task (ooc - they are not hidden and easy to spot now that Portho knows what to look for. I will also make some assumptions to speed things up a bit)
Pressing his ears to the door he can hear nothing so presses the button, always on the ready.
As the door opens he can get a glimpse of another room with another door to the far side, and possibly a corridor to the east but at the same time he catches movement of something big and hairy. Another spider, the same size!
(Map updated. Portho still has time to push the button and close the door, assuming this door works the same way as the previous two)
Not wanting to waste time and lose the remainder of the Invisibility spell Portho decides to try the same trick as before, he steps back around the corner, leaving his everburning torch on the ground where he had dropped it before pushing the button.
[Step back to H21]
He then quickly utters a spell, and creates 4 glowing spheres resembling willow wisps [Dancing lights, he creates the spherews in H19, H20, I19, & I20]
He then dircets the lights [No concentraion required] to move to F20, F21, G20 & G21 before moving up near the ceiling then slowly drifting north into the other room, hoping the spider follows the potential food source.
It seems the trick works! The spider moves north, following the lights. The giant vermin doesn't even notice the breath or smell of the gnome even though cold sweat beads on his forehead as one of the spider's legs almost touches him.
[please keep track of the spells used for the day on your sheet, i.e. write "2" in the "# cast" cell next to "dancing lights", 1-1-1 to mirror image, invisibility and sculpt sound. And maybe there was a detect magic as well, right?]
[OoC The first dancing lights was my 1/day spell-like ability, and I used a charge of my wand of detect secret doors, not detect magic. But point taken, will check off spells used per day for each level. I'm spontaneous, not prepared though so I don't need to mark individual spells, just slots.]
As quickly as possible Portho moves the lights further north, into the room with Ruby's corpse, then scoots up and presses the button that will close the north door behind it.
He then moves back to the south door to get out of the way.
Once satisfied that the north door is closed and the spider trapped, he will pick up his everburning torch and move into the room the spider came from to investigate.
Portho looks around carefully and finds the usual button on the far side of the new hall. The southeast corner features a side tunnel that ends in a flight of spiral stairs arching up and south.
Portho realizing that the cocoons could very well be dead or dying spider meals decides to investigate. He sets the everburning torch on the floor just inside the entrance to the room, then fishes the masterwork shortsword out of hus haversac. Using it in both hands as a machete, he works his way to the furthest north cocoon [J32] and then will carefully cut it open. He watces very warily, ready to scramble back in case whatever is inside is hostile.