Wasn't Field Trip a wonderful ep?  Alternate reality but they remember it and it changes their behavior. I loved the way that, in their hallucinations, they wove through their self-perceptions, assumptions, and views of the other to keep coming up against "truth" as the standard against which they measured themselves. I loved the fact that we got Mulder's fantasy Scully and his real Scully as well. I loved the way they actually entered each other's later hallucinations (at least that's my interpretation).

So, what was what? I'm a little nervous that no one else has posted, so I'll go out on a limb and say what I saw.  (Two viewings so this is still Class A. Be gentle if you think I'm nuts.) Where did reality start and finish? Let's put the teaser aside for now. Mulder and Scully's conversation in their office was real, including his very significant plea that she owed him the benefit of the doubt. Their trip to NC was also real up to the point that he took off for the field site looking a little wounded that she had chosen to stay with the body (C'mon, Mulder, how many times have you insisted that she stay with the body?) As soon as his car hit the mushroom, though, it was fantasy time for Mulder. His cave encounter with with Schiffs played out all of his assumptions about aliens and abductions, gratifyingly so for him, up to the point when he noted that the fake bodies weren't part of the textbook abductions. Little nagging doubt number one. The bright light and rumble = Scully poking into the cave. He went toward the light which suddenly translated into him going to the door of his apartment to greet Scully.

The apartment scenes with the Schiffs and aliens continued to play out Mulder's alien fantasies (how benign his abducted alien was) and his fantasy that Scully might come to agree with him completely. His longing for her simple assent was obviously still on his mind from their opening conversation. How romantically he played it, his tone of voice, his facial expressions, his touching her, his taking her into his bedroom. This was a moment of almost private passion between them (in his imagination) as they came to be of one mind: his mind. Everything he believed and all of his strange intuitions were vindicated by her agreement and by her ability to participate in what he sensed, set off by that moment when she heard the alien herself! Only, she also seemed to abandon her self and her science at the same time. And when she dismissed the bog drippings he felt nagging doubt number two: this could not be the real Scully. The hallucination dissolved.

The second hallucination was Scully's. As she went up the hill, she kicked open one of the mushrooms. Everything from that point was her dream. Rather than walking away from the cave, we later learn that she must have entered it. The arrival of the coroner, their finding Mulder's footprints and body: all a product of her horrified mind. Her fears for Mulder were already present when she could not get him to answer the phone. Under the influence of the mushroom it all became real. (Was anyone else waiting for "Go Ask Alice"?) Whereas Mulder fantasized her agreement with him, her mind was overwhelmed with the doubts about her role as the scientific counterpoint. She knew that she did not have the truth and was horrified to think that others took her ideas--only half of the whole and meaningless without Mulder's other half--as final. She turned Muldery herself, angry and shouting and insisting that that they must pursue the unanswered questions until, at the wake her vision turned to yellow goo. I think this was the end of her hallucination and that we switched back to Mulder, or rather Mulder's hallucination with the real Scully present in it.

When he walked through the door, he turned to her and said her name in that same seductive voice he had used earlier. It seemed to me that this was Mulder's Mulder, feeling nothing but affection for his partner. Her reaction was stunned, but also panting. Not sure whether we should interpret that panting or not! In their conversation, he presented his thoughts and she demanded evidence that he did not have. She asked how they got there, feeding his doubts, then hers, and she stated that what they were experiencing was not real. She recounted her theory about the mushroom based on her experience. He then agreed, filled in the last line and Mulder (I think?) concluded that they were still in the cave. (Didn't he say "we" not "I"?) I would have thought that this was Scully's hallucination, except that she then dissolved. I think that meant that it was his, but that she had entered into it with information that he did not have.

Next hallucination I think was hers with Mulder fully entered into it. When they were in Skinner's office, Mulder began to point out the inconsistencies (no burn marks, they can't break out of a hallucination just by consciousness of it, etc.) and then tested his theory that the scene wasn't real by shooting Skinner. Anyway from what he was saying I would have thought it was his hallucination, but then he dissolved at the end. This image of him shooting came from her subconscious, not his, from the time that he pointed his gun at Cassandra and other times that he had held people at gunpoint. Yeah, I know that she has done this, too, but I think that image of rash and possibly disastrous action enters into her view of him. Just as she entered his hallucination to argue the evidence, he now entered her hallucination to debate and take action.

At the end, of course, there was the wonderful scene in the ambulance when he reached out for her and she, not even looking, reached back for him. Unlike Dreamland when they seem to have remembered almost nothing but a sweet feeling, here they have both learned and remembered something about their partnership: neither is right or wrong, but it is what each brings the other that gives them their power and meaning together.