Volcano
After the teleport, Monica awakened in complete darkness. Rocks pressed on her face and right side, and her head hurt like during a light hangover. Yet, memories of the recent events quickly invaded her, forcing her to put aside the discomfort and straighten her position.
Monica's first instinct was to call for Khan, but he would have reacted faster than her in that situation. She could immediately realize that he wasn't there, and making noise wasn't ideal when she had yet to understand where she was.
While standing up, Monica came into contact with more rocky surfaces. A whole wall was on her right, and stretching her arms upward revealed a short ceiling. She was in a tunnel of some sort, and the lack of sounds in her surroundings told her she was alone.