Once Obi-wan received the message, the other Jedi Masters also headed to the lower level to get some answers.

Once they all were gathered, they saw a different kind of Maul. He wasn't the scared fearful apprentice who just lost his master. He looked as solid as stone as if he had no emotions. His eyes told them nothing, except for a small flame that unsettled all of them. What they saw now and had seen before were two completely different personas. And this one was completely crossed with Master Windu who was shouting questions at the new Maul.
"Damn it tell me! Who in the Force is 'My Lord'?!" Master Windu snapped
"My Lord is my Lord." Maul responded with all the calmness in the world. As soon as his eye caught sight of Obi-wan, he walked away from Master Windu like he wasn't even there. He walked over to Obi-wan and kneeled down.
"My Master, I must take you away from here." Maul spoke and Obi-wan jumped in reaction to this new Maul.
"Away from here? But why?" Obi-wan spoke in surprised and shock
"My Lord is near and he wishes you harm. If you want any chance of survival you will come with me my Master." Maul spoke giving the demands this time.
"I told you Maul. Stop calling 'master', I thought you chose to call me Kenobi." Obi-wan said more calm
"I, did?" Maul stated in a questioning tone. The Zabrak Jedi watched Maul studyingly as if he's noticed something.
"Of course I did. My apologies Kenobi, it must have slipped from my mind. It will not happen again." Maul concluded standing up.
"Maul, tell me, who is 'my Lord'?" Obi-wan asked and Maul's body shook like it had been shaking for a while. He stayed quiet.
"Maul?" Obi-wan asked and everyone in the room was confused from this sudden shift as Maul shook his head rapidly refusing to answer as he grabbed his head.
"Maul, please. We must know who that is up there." Obi-wan placed a hand on Maul's shoulder.
"I-I can't. He made me swear! My mas- my old master made me swear to silence!" Maul looked up into Obi-wan's calming eyes.
"Sidious is dead now Maul. What ever promises, what ever links, what ever anything to him you have dissolved when he died. Now Maul, tell me, who is up there? Who is that dark presence?" Obi-wan said sternly to Maul. Maul looked down away from Obi-wan's eyes shaking unable to answer. Obi-wan placed his free hand under Maul's chin forcing him to look into his eyes.
"You will receive no punishment for telling me Maul and I will take us somewhere safe until who ever that is, is captured and unable to do anyone harm." Obi-wan said staring directly into Maul's eyes.
"Plagueis. Darth Plagueis. He was... my old master's master." Maul said slowly as he kept staring back into Obi-wan's eyes.
"Another Sith Lord?!" Master Mundi exclaimed
"But I thought there could only be 2 Sith. You were the apprentice and I killed your master, how does that work out? I thought the apprentice had to kill the master to take on an apprentice." Obi-wan's voice was calm and steady
"I... was... in the beginning, not an apprentice. My, old master was the apprentice. When he took me, his master had no clue. I was around.... five when his master found out. He demanded that I be trained as an assassin. So I was for some years, until my old master wanted me as his apprentice so he could become more powerful to strike down his master," Maul started to explain
"But I killed Sidious before he could make an attempt on Plagueis." Obi-wan finished Maul's sentence.
"So even Sith break the rule of two." Master Windu spoke up.
"If this Darth Plagueis is how the Sith Apprentice described him, than he his more powerful than Sidious was." Master Mundi thought out loud.
"And I could hardly get the upper hand against him. Obi-wan was only able to defeat him by taking him on by surprise." Qui-gon added
"And it won't be easy taking a Sith Lord by surprise. He thought I was dead, that was my only advantage." Obi-wan said looking away from Maul, until everyone felt a shift in the room.
"I will attack him." Maul said lowering his hands from his head no longer hesitate or fear with his words.
"What?" Obi-wan looked back at Maul seeing the same look in his eyes that he did when he entered the room seeing Master Windu shouting at him. His hand dropped from Maul's shoulder.
"He will not expect it. He will expect me to obey him. He's made it clear to me before on several occasions that he is stronger than my master and I combined when we were just training. He thinks I would never dare to attack him. He is here to collect me. Since my old master is dead, I serve no use to him." Maul explained and the 'new' Maul had once again shifted back.
"Since I am no use to him and Kenobi sir is a Jedi. He will not allow me to change. So he wants to stop it. Tie up the last of my old master's loose ends." Maul went on
"He's wants to kill you." Obi-wan said placing both hands on Maul's shoulders. "If you attack him, you will surely die."
"Wouldn't it be better to die in battle?" Maul asked looking straight into Obi-wan's eyes. Obi-wan couldn't believe what he was hearing. Did Maul really think there was no way he'd survive?
"You will not engage Plagueis in a duel." Obi-wan stated firmly
"You will not have a surprise than. If I attack him, than you or the Jedi can finish him while he's focused on me." Maul stared into Obi-wan's eyes confused on what the plan will be.
"If Sidious was truly Senator Palpatine, he's been hiding right under our noses. What if Plagueis does the same?" Master Mundi asked
"I know him. I can spot him from miles away even if hides himself. If you want to end him, Kenobi sir, than you must do it with a surprise. He... has powers that no Jedi will be able to comprehend." Maul said never taking his eyes from Obi-wan's.
"The Sith Apprentice is right Padawan Kenobi, if what he is saying is true, and Darth Plagueis won't expect an attack from him, we will need it. We do not know when Darth Plagueis will attack. We have some ysalamiri that we can take with us. We can be hiding around building and with the ysalamiri, when the Sith Apprentice attacks it would take Darth Plagueis by surprise and when we go to join the attack we also will be a surprise to the Sith Lord." Master Windu spoke up leaving no room in his plan in rescuing Maul from the fight.
"Fine, but when we go to attack Darth Plagueis, I will not fight him to kill him. I've killed enough already. I will fight Darth Plagueis to rescue Maul from being slaughtered." Obi-wan forced into the plan.
"We will need as many Jedi as we can if we want to kill this Darth Plagueis Padawan!" Master Windu objected "You must be focused on ridding the galaxy of its worst threat!"
"I am a Jedi, Master Windu, and I want nothing more than to keep this galaxy safe, but I will not allow an innocent to be killed if I can so help it." Obi-wan snapped at the Jedi Master.
"That creature is far from innocent Padawan!" Master Windu snapped back
"Didn't you here Maul?! Maul said the Darth Plagueis wants him dead because he fears that Maul will become a Jedi! If someone is said to be so powerful, why fear something than?! If he fears that Maul will become a Jedi, that gives us the right to protect and save him! Not throw him to his death!" Obi-wan retorted at Master Windu. Qui-gon placed a hand on Obi-wan's shoulder and looked straight at Master Windu.
"I agree with my padawan, we are suppose to save every living creature we can. If my padawan thinks there is a big enough chance that we can save Maul from being killed than we should take that chance." Qui-gon spoke and Maul couldn't help, but keep his eyes on his new master in awe. His new master wanted to save him from death, even though the chances were slim.
"I agree with them." Master Mundi spoke up
"And I too." The Zabrak Jedi added outvoting Master Windu.
"Alright than. We all must get ready for the arrival of this Sith Lord." Master Windu said sighing in his defeat.

(Alright everyone! For those who don't read the Star Wars books, which is understandable since it is the EU now, a ysalamiri is a lizard creature that is able to create a bubble around itself that is able to cancel out all kinds of Force readings making it seem like nothing exists within that bubble. If there are enough ysalamiri around in one area it will cause their bubbles to join together causing a great bubble that will stretch for miles making all Force readings impossible.)