Warning! The following contains spoilers for the NCIS episode "Blood and Treasure." Read at your own risk!
NCIS revisited Gibbs and Fornell's off-the-books opioid investigation in the procedural's fall finale, and the episode did bring Fornell one step closer to finding the party responsible for the drugs that put his daughter's life in danger. Unfortunately, it also seems to have led to Fornell's meddling being discovered by some bad guys, as Gibbs was unable to track him down at the fast-food joint he was working deep cover at.
Fornell was working at the fast-food joint because it was the only lead they had following the death of a high-profile drug pusher they were pursuing. That drug pusher worked at this fast-food restaurant, which seemed weird to Fornell and Gibbs considering the money he would've made illegally. It led Fornell to take a job at the burger joint, hoping to find some connection between the place of business and the opioids.
Fornell's instincts were spot on, and after obtaining privileges to the fast-food joint's freezer, he found a stash of drugs. Fornell contacted Gibbs and told him to meet him at the business in two days to discuss their next move. Gibbs wrapped up the NCIS team's unrelated mystery and met up with Fornell the way they had established at the episode's beginning. When he arrived at the drive-through expecting Fornell, he was met by a manager, who told him Fornell hadn't been to work in a couple of days. The manager followed up asking if Gibbs knew him, which Gibbs obviously lied about.
I'm assuming that the audience was supposed to wonder if the manager was tied to the opioid operation, but I'm here wondering if we just saw the beginning of how Gibbs got in a situation where he eventually shoots McGee twice with a sniper rifle. It was a confusing flash-forward at the time, but if Gibbs had to break bad with opioid dealers in order to save Tobias Fornell, would he fire shots at McGee?
Better question: is the NCIS team still out of the loop on Gibbs' off-the-book activities in the flash-forward? I theorized in earlier episodes that the scene was a misdirect, and that McGee had some fake blood packets or something to make the shots fired at him look more convincing. If the team isn't in on the operation, however, it could be that Gibbs is pulling the trigger on his team member, hoping no one finds out and that McGee will ultimately be okay.
The latter just doesn't sound like a Gibbs move. NCIS generally shows him to be the guy who is a step or two ahead of the bad guys. This is what makes me think he wouldn't stoop to such lows in cooperating with criminals unless lives were on the line. Namely, Fornell's. I could be wrong though, and it's possible we could see him before the craziness of that flash-forward scene is resolved.