In the middle of the recording sessions, which took place between October and November 1998, Petrucci had to leave the studio when he got word that his pregnant wife had gone into labor.

In Petrucci's absence Levin, Rudess and drummer Mike Portnoy recorded dozens of completely improvised jams, many of which would eventually be released on the 2007 album Spontaneous Combustion under the group name Liquid Trio Experiment.

Portnoy alluded to the jams in the liner notes, stating that "if you dig this, there is A LOT more where it came from..." When Petrucci returned to the studio in November, he wrote and recorded guitar parts for two of these improvisations: "Chewbacca" and "Liquid Dreams".

For "Chewbacca" in particular, he took the time to learn several of Rudess's improvised melodies and doubled them on guitar, which in Portnoy's words "(gave) the illusion of written composition".

Shortly after Liquid Tension Experiment 2 was released, Rudess joined Dream Theater as a full-time member.