John breathed a little easier when Strange agreed, however begrudgingly. If they made it out of this without anyone getting killed by the machines or the Resistance, it would be a miracle. But, for right now, if he could keep his team alive and gain Derek's trust enough they could spring them from the camp, John would call it a win. They could see what the larger picture looked like once they were out of there.
Taking the knife, he moved to kneel next to Strange, his body angled so the proof of humanity would be visible, but the quiet Thank you he murmured as he held the knife point to Strange's skin would be hidden from everyone else. John made it as quick and painless as possible, a short, super shallow cut that was barely more than a mild papercut. All they needed was visible blood to prove humanity.
Then he stood and handed the knife back to Derek's soldier, still keeping himself between Strange and Derek until Strange could pull himself back together. He knew that look in Derek's eyes. There would be questions later. Hopefully, John would be able to answer them without risking the mission, his team, or his uncle.