Shikamaru would initially be his calm and collected self, analyzing the situation in the cave. Naruto, on the other hand, would be full of energy and eager to find a way out. But as they face difficulties together, like a shortage of food or water, they would start to comfort each other. Shikamaru might even show his vulnerable side to Naruto, and Naruto would respond with his characteristic warmth, leading to a deeper emotional connection and more loving interactions.
They would probably start with some light - hearted banter. Shikamaru might complain about the situation while Naruto tries to stay positive. As time goes on, they would become more open with each other. Naruto could share his hopes for the future of the village, and Shikamaru would listen intently. Their interactions would gradually turn more affectionate as they realize their feelings for each other in the cave.