The soldiers recognized their position was untenable. A new crowd had gathered atop Blanket Hill, and they were effectively caught against a high chain link fence if the crowd decided to advance upon them. The soldiers recognized the time had come to retake their position atop Blanket Hill, next to Taylor Hall.
Halfway across the practice field, the soldiers stopped for some reason (which they never disclosed during the investigation) to confer before resuming their march.
The soldiers could have used this "huddle" as a time to plan their strategy. If they decided to march to the top of Blanket Hill, turn and fire upon the crowd of students in unison, the soldiers were guilty of murder.