Is Fitz taking a moment to consider the repercussions of using the machine? Is his quest for Simmons worth unleashing more aliens into our world? Remember, something was chasing Simmons on that planet.
Is Fitz asking for Mack's help here, or is the big guy questioning the mission? Mack has proven himself consistently level-headed. Isn't is possible they might open a portal allowing Kree warriors to cross through?