This honestly wasn't Thor's intention, but when he felt Diana's lips against his, he couldn't help the change in his expression. His eyes widened considerably when she kissed him, and for the attosecond it lasted, he reveled in it, like he didn't believe it was really happening. That sealed it that he was either asleep or being tortured by some ghost.
Diana jumped back like she'd been shot out of a cannon and Thor's eyes followed hers, looking for the threat. His eyes glowed with that electric power again for the briefest moment, until he saw nothing. Even he could connect the dots on what happened, but not exactly how or what she saw. Clearly, the other ghost she'd mentioned, likely this Steve Trevor, had chosen that moment to intervene, scare her and break up the moment.
"Are you alright?" He asked without frustration or anger at the interrupted moment. His only concern was her well-being. When she explained about the ghosts, he nodded his understanding. "Maybe that's a sign we should turn back for now? The sun is starting to peak over the trees on the east side of the clearing."