Complex sentence: It was in this dimension, when Professor X and Wolverine made physical contact with each other and merged with Logan's body Xavier lept into the mouthpiece of Juggernaut's headpiece, however this immediately forced them to separate from one another.
Split into simpler sentences: It was in this dimension that Professor X and Wolverine made physical contact with each other, and Xavier, merging with Logan's body, leaped into the mouth of Juggernaut's headpiece. However, this immediately forced them to separate from one another.