One possible reason is that she might be anemic. Lack of enough iron in the body can lead to anemia which may result in fainting spells. Standing up too quickly can also cause a drop in blood pressure and make her pass out, this is called orthostatic hypotension. Additionally, certain medications she might be taking could have side effects that lead to fainting.
There could be several reasons. One common reason might be a sudden drop in blood pressure. Another could be related to underlying heart conditions that are exacerbated during physical exertion. It could also be due to a lack of oxygen, perhaps if there were some sort of airway obstruction during the activity.
One reason could be that he was under a dark spell cast by a new enemy in the fanfiction. Maybe some dark wizard or witch sent a spell his way before he boarded the train, and it took effect during the journey.
In some fanfics, Deku might pass out from lack of proper rest. He's always so determined to be a hero that he might neglect his own well - being. So, continuous days of little sleep and high - stress situations could lead to him collapsing. Additionally, if he gets poisoned or affected by some sort of harmful substance in a fan - created scenario, that could also make him pass out.
One reason could be that she wants some alone time. Maybe she's feeling stressed at home and just needs a break. For example, if there are constant family arguments or too many household chores piling up, she might feel the need to escape for a while.
She might be going out to meet friends. It could be for a coffee or just to have a chat and catch up.
One reason could be extreme physical exhaustion. For example, if a character has been running for a long time to escape from danger, like in an adventure novel where the hero is being chased by villains through a forest for days without proper rest or food. Another reason might be due to emotional shock. Say, a character discovers that a loved one has betrayed them or has passed away suddenly. In a mystery novel, a detective might pass out when he finally uncovers a particularly grisly truth that he was not prepared for. Also, it could be because of a physical injury. In a war novel, a soldier who gets seriously wounded might pass out from the pain and blood loss.
Another reason might be related to a new piece of technology. For example, if there was a malfunction in some experimental Stark Industries device that emitted some sort of energy wave. Pepper, being close to it, could have been affected and passed out as a result.
Well, it's a complex situation. She might be in a mid - life crisis or having some sort of identity crisis. Maybe she has a wrong perception of what is acceptable behavior in a social or marital context. It could also be that she has been influenced by some new 'friends' or a new social group that has a very different set of values. Another possibility is that there are unaddressed relationship issues between you two, like feelings of neglect or unhappiness, which she is expressing in this extreme and inappropriate way.
One possible reason could be that she has a very different view on nudity and privacy, perhaps influenced by some extreme liberal ideas. But this is still not acceptable in a normal social context.
She might be stuck in traffic. Traffic jams are quite common, especially during rush hours. Another reason could be that she went for some after - work social activities. For example, she had a drink with colleagues to celebrate a colleague's birthday or a work achievement. Or she could have been helping someone out, like an elderly neighbor who needed assistance.