MaxFulvus: Thanks for killing the Beholder but I don't understand why you want to risk your life for possible loots intead of going through the portal ? I won't come back to the opposite of the room just for your greediness and I'm a dwarf too, so I know what's I'm talking about. You know, when you die, you find other priorities in life, like keep it and appreciate it, for example.
And where do you see a treasure ? From where I'am, I only see the remaining Beholder and some traps in the center of the room, surrounding by spikes ! It doesn't worth it, trust me, brother.
But if you really want to play with your fate, I suggest you to ask to Dunward to levitate to the treasure and bringing something for you, or maybe to carry you directly to it to avoid traps on the ground ?
About myself, I consider the portal is safe to go through. I remain prudent but I quickly move towards it, then before to enter, I turn back and give a last advice to the other adventurers : "Carry Roosevelt and Aslain and bring them beyond the portal. Roosevelt can be resurrected and Aslain awaken after we entering the portal. Too bad that some of our fellows where left behind, but it's their choice (I have a thought for Babargh who was a good guy !). See you later !".
Then I enter in the portal, hoping to find a safe place to take some rest, even if I will never forgotten the horrors hidden in the dark corners of the Earth. It looks like you've completely skipped my post and some others, since I've asked if someone can carry Roosevelt since I'm carrying Rudy, and Sulibor picked him up. I've actually also wanted to go exploring the room, since the Beholder must have had a good a reason to be here, and with the hallway cleared, it should be easy for a thief like you to trapcheck the room (esp. with infravision, so you can see well in the dark, and I have a torch to light the way).
Just think, the only danger is traps, which you're good at detecting, and we might find a pile of treasure lying in a corner or hidden in an alcove triggered by a secret switch or lever! Aren't you interested why was the beholder here, whether this is his lair and what's in this hallway, besides the portal?