Other mistake: Sky's dress has no bullet holes, although she was shot twice in the stomach.
Other mistake: Agents say they have seen seismic activity in South Dakota, but from earlier episodes, Daisy and Lincoln visit South Australia to find out Fire Guy.
Other mistake: The module on the alien spacecraft Fitz repairs, most visible when he says "OK we're done, we're done" is just a standard PC motherboard, which also has no connections to anything else - it's just glued to the metal panel he's holding.
Chosen answer: Coulson believes he was resuscitated then sent to Tahiti to recuperate. "A magical place," he calls it. But in the "Agents of S.H.I.E.L.D." episode "The Magical Place", Coulson, through a mind-reading machine, learns that he was treated by S.H.I.E.L.D. and a fake memory of Tahiti was placed as a "mask" of sorts over the painful memory of the operation, which involved a drug seemingly of alien origin to repair the damage, coupled with a lot of morally dubious surgery.