From the 11K:
“000404: He [Seth Houy] then could see the student named John Savage under the table that was over and back from his. He said that John was just sitting on his butt holding his legs and leaning his head against the bottom of the table top. One of the suspects said, "Who's under that table?" John said, "John Savage." One of the suspects said, "You've never done anything to us, we'll let you live. Run."
“000554: [John Savage] Anyway, when they came to my table Eric stuck his head under the table and pointed his gun at me, so I scooted out of the way of the barrel, and then he pointed it at me again, and I scooted back out of the way .Then he stood up and said, "'Who is under the table? Identify yourself!” And I said, "It's me, John!" and Dylan said, "John Savage?” And I said, "Yes!" and Dylan walked over to my side of the table and said "Hi." And I said, "Hi Dylan, what are you doing?" And he shrugged and said, "Oh, killing people. " And I said, "Are you going to kill me?" And he looked at me for a second and then he said, "No, dude, just run Just get out of here.”
“000556: [John Savage] Eric was looking under the tables and came over to the table where Savage was hiding. Enc pointed a gun at Savage and asked who was under the table. Savage identified himself by saying "It's me, John.” Dvlan asked "John Savage?" and Savage replied. "Yeah." Dylan came over to the table and said “Hi." Savage looked up and said "Hi. Dylan, what are you doing?" Dylan shrugged and said. "Killing people." Savage asked "Are you going to kill me?" Dylan stated, "No. dude run. Just get out of here.”
“000570-000571: John Savage reported he next observed Eric Harris walk between the bookshelves in a westerly direction, stopping just to the west of Table
[You must be registered and logged in to see this link.]. John Savage indicated at that point Eric Harris was standing close enough that he could "reach out and touch him.” John Savage reported Eric Harris next "squatted down and points that carbine right at me." John Savage stated instinctually he leaned forward trying to avoid having the weapon pointing directly at him. John Savage stated as he leaned forward, Eric Harris repositioned the carbine rifle so it again was pointing in his direction. John Savage stated he subsequently leaned back, again to avoid having the weapon pointed directly at him. John Savage stated Eric Harris then stood up and stated, "Who is under this table, identify yourself." John Savage stated he responded, "It's John." After responding with his first name, John Savage related he then heard a voice he later identified as Dylan Klebold's coming from a southwesterly direction. John Savage explained he heard Dylan Klebold ask, "John Savage?" John Savage stated he responded, "Yeah." At that point John Savage recalled Eric Harris walking up to the north end of table
[You must be registered and logged in to see this link.] while Dylan Klebold approached table
[You must be registered and logged in to see this link.] from the west. John Savage stated after Dylan Klebold had walked up to the west side of table
[You must be registered and logged in to see this link.], he then looked up and "made eye contact with Dylan." John Savage stated after making contact with the forenamed, he said, "Hi Dylan, what are you doing?" John Savage related Dylan Klebold responded by shrugging his shoulders and replying, "Oh, just killing people." John Savage then asked Dylan Klebold, "Are you going to kill me?" According to John Savage, Dylan Klebold responded, "No dude, just get out of here, just run." John Savage stated Dylan Klebold may have told him to "run" more than once as if to indicate he should hurry.”
“011144: Witnesses report Eric Harris and Dylan Klebold then passed through the east side bookshelves in the center section where another reloading process took place at table
[You must be registered and logged in to see this link.]. During that time Enc Harris was seen walking north through the center section to the south computer table where he gained access to the blue backpack reportedly containing ammunition. Eric Harris then returned to an area near table
[You must be registered and logged in to see this link.]. While at that location Eric Harris asked a student under table
[You must be registered and logged in to see this link.] to identify himself. The student identified himself as John Savage. Eric Harris then moved north of table
[You must be registered and logged in to see this link.] as Dylan Klebold made contact with John Savage. Dylan Klebold eventually told John Savage to leave the library, which he does.”
“025660: Investigator Art Peterson interviewed Columbine High School student John Savage. Savage stated that during the shooting he was hiding under a table in the library. He recognized Eric Harris and Dylan Klebold, both wearing black. Dylan Klebold pointed a black handgun under the table at Savage. Savage said, "What are you doing?" Dylan responded, "We're out killing people." Klebold told Savage to identify himself and Savage responded, "It's John." Savage then asked, "Are you going to kill me?" Klebold responded, "No. run. just get out of here."
So apparently John had a theater class with Dylan, as well as spending quite a lot of time together in the sound booth preparing and during productions. My question is: what is the connection with Eric?
Personally my thoughts are the reason why Dylan let John go/escape is because even up until that point both boys believed the bombs would detonate and the lunchroom and library would explode, killing everyone in these locations. They needed at least one person to live in order to have their story told- after all, remember in the Basement Tapes the boys discussed who should have the honor of directing their movie. An added bonus is that they picked someone who would humanize them/show compassion and not make them out to be heartless monsters. Even years later Savage would talk about both boys in a compassionate manner. However, they were probably already so far lost and tuned out on life by April 20 that they didn’t even think of that.
IMO, the only reason why Eric let Brooks live is because he didn’t want to bust the plan before the bombs exploded.