Brandon Bryant is a former drone operator (aka drone sensor operator) for the U.S. Military.
At 4:54 Bryant states, "... there's a lot less mistakes than an F-16, but it's still made me feel like, like I just ended a human life, you know ... ah, how is anyone supposed to deal with that?". During the 5:01 - 5:02 segment (underlined) the former Drone operator beautifully exemplifies a combination of two different emotions felt simultaneously - that of empathy and disgust.
Bryant's central forehead muscle contracts and is somewhat subtle and higher up in this particular moment and example (in ellipse withing photo below yet best see in the dynamic context of the video). Whenever one feels either emotional pain or physical pain directly for oneself or indirectly for another via empathy - the central forehead contracts (take heed though, for there are other contexts for a CFC).
The CFC is also accompanied by an elevation of his inner (medial) eyebrows.
Disgust in the former drone operator's face is shown by a bilateral nostril flaring and a tightening of his "mustache area" (referred to as such regardless of gender or absence facial hair) along with an evanescent deepening of both nasal-labial folds. And although not required for disgust, the partial closing of Bryant's eyelids here amplifies his disgust.
The fact that Brandon Bryant displays these facial expressions in this context in highly consistent with one who experiencing as well as predicting who is prone to developing Post Traumatic Stress Disorder (PTSD).
From a nonverbal communication standpoint, this interview is a fantastic teaching video. What other telling body language did you spot?
Negotiation Nonverbal Communication Secret # 1499: Bill Clinton's Empathy for Eric Fehrnstrom and Mitt Romney ... What's Your Sincerity Quotient
Nonverbal Communication Analysis No. 2565: Goblin Valley State Park - Knocking over Hoodoo Rock Formation - Body Language of Boy Scout "Leaders"
Nonverbal Communication Analysis # 1732: Rationalization, Rapport, Empathy Expression How Jewel got her name
Nonverbal Communication Analysis No. 2512: Matthew Cordle's YouTube Confession and the Death of Vincent Canzani "I Killed a Man" - What His Body Language Tells Us ... It's NOT what you think!
Nonverbal Communication Analysis No. 2537: Kenya Mall Attack Witness, Body Language Tell
Nonverbal Communication Analysis # 2390: Charles Ramsey Interview & Cleveland Kidnappings - Sarcastic Disbelief, Disgust and Exclamation
Nonverbal Communication Analysis No. 2507: Secretary of State Kerry's Disgust An Oft Overlooked and Camouflaged Body Language Signal