John Arthur Benn blacked out somewhere in the limbo of the pre-Christian era, as he'd been warned he might, and when he came to he found himself lying in a rather uncomfortable heap with his head in a mushroom patch. The mushrooms and the trees around him weren't shrinking any more, so John knew he'd stopped—or at least was going very slowly. After a while he decided he wasn't going at all, and got to his feet.
It seemed very pleasant here, in the woods, so he found a fallen tree to sit on and took a wrapped sandwich and a small vacuum bottle of coffee out of his pocket. When he'd finished his meal he walked to a stream nearby, rinsed the bottle, tossed the waxed paper onto the water to be carried away and pocketed the vacuum bottle.
Now, he thought, what? This was scarcely dinosaur country. At this point a wild boar chased him up a tree. To be killed by a boar would be ignominious, after all this, although the animal was well enough tusked to have done the job, and so John Arthur Benn climbed to a high branch, where the boar's persistence forced him to spend the night. He slept, somehow, and, with the closing of his conscious mind—the one that wanted to meet a dinosaur in fatal combat—the conventional subconscious, which also sought suicide, but in a more familiar way, shifted him out of reverse.
When he awoke, he was back in 1956, in Philadelphia. Irrevocably, John Arthur Benn knew.
He went home and hanged himself in a closet.