Bava Kama page 23. I am wondering what the argument between Abayee and Rava is about

Bava Kama page 23. I am wondering what the argument between Abayee and Rava is about? Abayee asked if R Yochanan is right (that damage by fire is liable because it is his arrows, i.e., direct damage by his body), then why would he be not liable for hidden things? And Abyee answered his own question. The case is when there was a wall, and it fell down, and he did not have a chance to repair it. Rava then asked, “If so, he should not be liable even for open things?” so Rava said, “Therefore, R Yochanan holds with Reish Lakish that fire is because of damage by means of one’s property, and the whole reason R. Yochanan said because of his arrows is because of four extra kinds of damage. My question is what is the case? Does Abaye mean that if there was a wall, and he lit a fire, and it went over the wall, that he would not be liable? But why? Supposedly he lit some kind of bonfire in his backway and there was a wall, and the fire jumped over it. Why would he be not liable? And all the more so, if there was a wall, and it fell, and he did not have time to repair it and still he lit a bonfire, and supposedly there too he would not be liable for hidden things and Rava said in that case even for open things he would not be liable. But this seems even worse. If there was no wall because it fell (even though he did not have time to fix it), if fire is because of his arrows, then he should be liable for both hidden and open things. Why was he lighting a bonfire? Maybe he was cold? But then, he should build the wall and then light the fire? The only way according to Rava to get the obligation to be on open things, and nonliability for hidden things, is if fire is obligated only because of damage by means of one’s property. ______________At any rate, I can see the point of the Gra that the Rif Rambam and Semag held that R Yochanan does not hold fire is because of his arrows except for the added liability of four kind of damage. The reason he knows this from the Rambam is that the Rambam wrote for fire one is not liable for hidden things. If we look at the discussion between Abaye and Rava, we see that if there was a wall, he is not liable for anything, and if there was no wall at all, then he should be liable for all damage unless fire is liable only because of damage by means of one’sproperty. I should mention that the way the Gra understands the statement of the Gemara is different than what the Gemara might appear at first sight. The Gemara says that R. Yochanan holds that fire is liable because of both his arrows and his property. That sounds like it means in all case it is liable for both. That is, “and” means this and that that as in intersection. The Gra understands the meaning is this or that, but not both. In some case fire is liable because of his arrows (in the case of the four types of damage one is liable for when damage is done by one body that are extra), and in other cases fire is liable for damage that would-be caused by one property. _______________________________________________________________________בבא קמא page כ''ג. I am wondering what the argument between אביי and רבא is about? אביי asked if ר’ יוחנן is right (that damage by fire is liable because it is his arrows, i.e., direct damage by his body), then why would he be not liable for hidden things? And אביי answered his own question. The case is when there was a wall, and it fell down, and he did not have a chance to repair it. רבא then asked, “If so, he should not be liable even for open things?” so רבא said, “Therefore, ר’ יוחנן holds with ריש לקיש that fire is because of damage by means of one’s property, and the whole reason ר’ יוחנן said because of his arrow is because of four extra kinds of damage. My question is what is the case? Does אביי mean that if there was a wall, and he lit a fire, and it went over the wall, that he would not be liable? But why? Supposedly he lit some kind of bonfire in his backway and there was a wall, and the fire jumped over it. Why would he be not liable? And all the more so, if there was a wall, and it fell, and he did not have time to repair it and still he lit a bonfire, and supposedly there too he would not be liable for hidden things and רבא said in that case even for open things he would not be liable. But this seems even worse. If there was no wall (even though he did not have time to fix it), if fire is because of his arrows, then he should be liable for both hidden and open things. Why was he lighting a bonfire? Maybe he was cold? But then, he should build the wall and then light the fire? The only way according to רבא to get the obligation to be on open things, and nonliability for hidden things, is if fire is obligated only because of damage by means of one’s property. At any rate, I can see the point of the גר''א that the רי''ף רמב''ם and סמ''ג held that ר’ יוחנן does not hold fire is because of his arrows except for the added liability of four kind of damage. The reason he knows this from the רמב’’ם is that the רמב’’ם wrote for fire one is not liable for hidden things. If we look at the discussion between אביי and רבא, we see that if there was a wall, he is not liable for anything, and if there was no wall at all, then he should be liable for all damage unless fire is liable only because of damage by means of one’s property. I should mention that the way the גר''א understands the statement of the גמרא is different than what the גמרא might appear at first sight. The גמרא says that ר' יוחנן holds that fire is liable because of both his arrows and his property. That sounds like it means in all case it is liable for both. That is, “and” means this and that that as in intersection. The גר''א understands the meaning is this or that, but not both. In some case fire is liable because of his arrows (in the case of the four types of damage one is liable for when damage is done by one body that are extra), and in other cases fire is liable for damage that would-be caused by one property.