The door is a heavy, industrial styled metal plate, with a large handle connected to it. You find that the door is not trapped or locked but operating it will send a magical alert to Arganth to make him aware of your presence. However you see that this is easily bypassed by not pulling the door handle, so with your thieves' tools you successfully remove the handle from the rest of the door without triggering it. Since the door is so large and heavy, opening it without the use of the handle requires an Athletics check to push it open. (Anybody is welcome to make the check)

Eggo Lass looks at the door and then back to her arms. "I'm not exactly the strongest here. But I suppose I could help if you want."

[[ That awkward moment when the wizard is stronger than you. ;p ]]

Hugh looks around, "My muscles are for fine movement, not massive movement."

Bilyur says, "I focus on optimizing a low amount of power, I'm not the strongest person out there, perhaps someone else could open the door, but I could be the first to go through."

Sly raises an eyebrow at Bilyur. "In wonder if the wall you toppled would agree with that statement."

"I'm not exactly a picture of brawn myself. Perhaps we could all try together?"

If that doesn't seem possible, Sly gives it a try: 11. If she gets advantage due to Eggo Helping: 15.

Sly manages to push the heavy metal door open and enters a room you feel is rarely visited by the cult. The only lighting is from Hugh's lantern and the residual light creeping through the doorway from the hall of lanterns, and with the room illuminated you can get a better look. The stone walls are bare, lacking any graffiti or even damage, and to the far east of the room an enormous, 10 foot by 10 foot circular gate blocks off access to Arganth's chamber. The gate is made of the same material as the metal door you just passed, and the gate has a huge lever like knob used to turn the door and open it attached to the front. Other then that the dingy room appears to be empty.

Bilyur grins at Sly, "I can probably break it quite easily, however, I thought we were trying to open it."

Hugh approaches the gate and examines the knob. Would it be possible to take the knob off like was done on the previous door?

If so Thieves Tools 27 to remove the knob.

If not, "The last knob would have signaled our approach, do we turn this one or explore other options we have passed?

Telepathically Eggo Lass asks Hugh, (Think that gate might also have an alarm attached to it?) She takes a glance with her devil's sight eyes.

She smiles at Bilyur's remark. (Indeed, breaking his door would probably not put us on good terms with the red knight.)

Perception: 17+3 = 20

Hugh examines the gate, and he feels that he could just manage to remove the lever if he tried, though he feels that it would effectively lock the door as none of you could even hope to shift such a huge metal object all on your own. Eggo Lass examines the door and finds that it is spell free, it seems that only the previous door was alarmed to warn Arganth of approaching adventurers or cultists trespassing a bit too far into the Red Knight’s domain. 

Sly remarks "We were told by two different sources that simply talking politely to the red knight is an advisable course of action. I am not sure how much good will we'll gain from dismantling his front door."

Looking at Hughs deft handywork, the wizard continues: "Although I suppose we could offer to re-attach this afterwards."

Bilyur suggests, "I suppose we should just walk in. I don't think that sneaking up on this guy is the best idea, and while I'm glad he doesn't know we're coming yet,, I think we should just open the door."

Eggo Lass considers the combination and Sly and Bilyur's thoughts. "Fair enough." she says. It wasn't her style but it seemed logical enough. "Perhaps we could also bring him a gift?" She looks around and in her bag, "Possibly some rations? I could provide one of mine and flavor it."

 "Possibly." Bilyur muses, stroking his forked beard.

"Over trained I guess. The gate is open, if we want to talk in."

Sly nods and shoves the door open with mage hand if possible and then peers in carefully.

The gate swings forward to open, and Sly sees that it leads to a dingy sewer tunnel that appears to come out in a large chamber area. The tunnel is slightly damp, and the floor has pools of muck with assorted footprints in them from where adventurers have went through.

Hugh walks in scanning the passage for anything hidden, traps, door, things of that nature. Perception 11

You find no secrets within the tunnel, though you do pick up the sound of rapidly rushing water echoing through the tunnel from the chamber at the end.

"Rushing water. Perhaps a place the knight would stay?" suggests Eggo Lass as Hugh takes the lead. "Should we follow it?"

[[ I assume it's also where the bootprints head. ]]