Warning: SPOILERS for Star Trek: Picard Season 2, Episode 8 - "Mercy"
Agent Martin Wells (Jay Karnes) in Star Trek: Picard season 2 is an unexpected Star Trek: Voyager crossover but Picard also missed out on a perfect way to link up with Star Trek: Enterprise. Wells appeared in 10 Forward at the end of Star Trek: Picard season 2, episode 7 to arrest Jean-Luc Picard (Patrick Stewart) and Guinan (Ito Aghayere) under suspicion of being aliens (although Wells was actually right about Guinan). But Wells' backstory could have crossed over with the Star Trek: Enterprise episode, "Carbon Creek."
Jay Karnes played Lt. Ducane in the Star Trek: Voyager season 5 episode, "Relativity." Ducane was a 29th-century Starfleet Officer on the Federation timeship Relativity. Ducane recruited Seven of Nine (Jeri Ryan) and Captain Kathryn Janeway (Kate Mulgrew) to help him identify a saboteur who would destroy the USS Voyager in the 24th century. Because Ducane enforced time travel, Voyager viewers naturally guessed that Agent Wells was really Ducane crossing over to Star Trek: Picard because Jean-Luc and his motley crew violated the Temporal Prime Directive. However, Star Trek: Picard season 2, episode 8, "Mercy," debunked that Wells was really Ducane. Rather, Wells is a 21st-century human who had a traumatic encounter with Vulcans when he was a boy that left him haunted and believing in alien life.
Unfortunately, Star Trek: Picard didn't seize the golden opportunity to connect to Star Trek: Enterprise's "Carbon Creek." In that episode, T'Pol (Jolene Blalock) told the story of her ancestor, T'Mir, who was part of a crashed Vulcan survey team that became stranded in Carbon Creek, Pennsylvania, in 1957. Although T'Mir and her colleague, Stron (Michael Krawic), were eventually rescued, the third member of their team, Mestral (J. Paul Boehmer), became fascinated with humanity and opted to remain on Earth. Because Vulcans are much longer-lived than humans, Mestral could have easily encountered the young Martin Wells during his travels since Wells would have logically met the Vulcans sometime in the 1970s.
Mestral is another alien who decided to blend in with humanity, which makes him similar to Guinan (Ito Aghayere). Mestral could potentially still be alive in 2o24. After all, Mestral was reported killed during the crash by T'Mir and Stron so it's unlikely he returned to Vulcan, and Mestral was too fascinated by humanity to want to leave Earth. It would have been relatively simple to make Mestral the Vulcan who the young Martin Wells ran into in the woods, rather than an unknown group of Vulcan surveyors. However, Wells' backstory in Star Trek: Picard season 2 does continue the fact that Vulcans visited the Earth numerous times before they finally made a formal First Contact in 2063 after Dr. Zephram Cochrane (James Cromwell) achieved humanity's first warp flight.
Considering how Star Trek: Picard season 2 connected to the Star Trek: The Original Series episode "Assignment: Earth" via Tallinn (Orla Brady), Renée Picard's (Penelope Mitchell) Romulan Supervisor, it's both surprising and a bit disappointing that Mestral wasn't the Vulcan Martin Wells met as a boy. Picard already referenced the OV-165 shuttle seen in Star Trek: Enterprise's opening credits. Plus, the Vulcans surveying Earth in 1957 wouldn't have been affected by Q (John de Lancie) changing the timeline in 2024. Regardless that Star Trek: Enterprise never happened in the Confederation's future timeline, Mestral preceded Q's time divergence by 67 years so the Vulcan is logically somewhere on the planet in Star Trek: Picard season 2.
Star Trek: Picard Season 2 streams Thursdays on Paramount+.