Complex sentence: Lisa, as she is slowly and cautiously being brought to the surface, comes out of her hallucination and also realizes her sister is not with her and starts to cry and call out to Kate, realizing that Kate may have been killed.
Split into simpler sentences: Lisa, as she is slowly and cautiously being brought to the surface, comes out of her hallucination, and also realizes her sister is not with her. She starts to cry and call out to Kate, realizing that Kate may have been killed.