There's lots of space in the sky... unless you don't get proper separation at break off, get twisted up with line twists, spin out of control and hit your friend under canopy, causing both of you to cutaway. Luckily both skydivers landed safely.
Sometimes we can't avoid line twists, but more horizontal separation from the group at break off would have allowed him to either kick out of the line twists (altitude permitting) or provided clear airspace to cutaway without hitting another canopy.
Best practice for break off on a tracking jump is to "fan out" away from the center of the formation; typically 45 degrees and no more than 90 degrees. DO NOT turn 180 degrees and track up jump run.