See Tosfos (s.v. Eelaima). Tosfos ask that considering the implication of our Gemara that there is no difference between moving the fire close to the item destroyed, or moving the item getting destroyed close to the fire, (as we see that moving produce to where the fire will consume it will obligate the perpetrator), why then does the Gemara in Sanhedrin 77a state that if one ties someone else in a place where the heat or cold will reach him and kill him, or, similarly, in front of a lion, he is not considered a direct murderer. He has merely caused the death of the victim. According to the opinion that holds Isho Mishum Chitzav (see beginning of previous post), then we should equate this to bringing the vehicle of death to the victim. Meaning, just as one who lights a fire that kills someone is a murderer according to this opinion, so too, based on this Gemara, should be someone who brings a victim to a place where fire (or, as in Sanhedrin, heat, cold, or wild animals) will kill him.
This requires explanation. In the case of bringing someone toward the fire, the fire was not propelled by the criminal, nor even ignited by him. How is there any way to consider the fire as "his arrows"?
Perhaps this can be explained based on R' Chaim Soloveitchik's comments to Hilchos Shecheinim (11:1) . In the matter of Isho Mishum Chitzav, there are two ways to define the novelty being conveyed by this formulation and categorization of Aish:
A - Although it is the wind that is transporting the fire, nevertheless, since he ignited it, we do not consider the wind's force as a mitigation of the human's action. On the contrary, we consider the wind as part of the human's action. Meaning, the Torah is telling us that when using the forces of nature in order to transport the Mazik created from point A to point B, this is considered the force of the human being. The reality of the ignition of the fire and its transportation are all traced back to be considered the force of the lighter of the fire. The Bircas Avraham adds somewhat more clarity to this by adding that just as the ability of the fire to burn and spread and consume is not considered extraneous, and hence exculpatory, to the human's input, but is considered part of the human's action, similarly the wind's intervention in transporation of the fire is considered to be employed by the human himself.
[It should be noted that the Chazon Ish in his glosses to R' Chaim there expresses difficulty with this interpretation of Isho Mishum Chitzav, and explains that when utilizes the force of the wind which is available immediately to propel the fire, this is considered Kocho]
B - Although in reality it is not the force of the human being used to propel the fire, nevertheless Halachah is informing us that just as when one shoots an arrow and utilizes his own force to propel it, he is culpable for the result, so too when one utilizes the force of nature to transport the fire he is just as responsible. These two cases, though distinct in terms of the reality of where the propellant forces are viewed as coming from, are treated Halachically without any difference.
It would seem that our Tosfos is following this second approach. Just as the Torah innovates that whatever the wind propels is Halachically synonymous with a shot arrow, despite the reality of the human involvement in propelling the arrow, since it is a force of nature being used to propel the fire and not a power source with any sort of cognitive input, similarly, when one brings the produce proximate to the fire, since he is using the forces of nature to damage the produce, this is also included in Chitzav.
[R' Chaim in Hilchos Shecheinim concludes that the first way of looking at Isho Mishum Chitzav is correct. R' Soloveitchik quotes R' Chaim as saying that indeed there is no application of Isho Mishum Chitzav in a situation of bringing something close to the fire, and that Tosfos' question is therefore moot. (See part B below) It seems clear that this is based on R' Chaim's conclusion. See also Bircas Avraham to 22b (Mahadura Basra) that R' Chaim explains Tosfos there (s.v. V'hayah) based on the second side of this Chakirah).]
[See Maharam Shiff to Tosfos that the question is inapplicable according to the view of Reish Lakish, Isho Mishum Mamono, since there is no question of culpability for murder even in a situation of lighting the fire.]
B. Additional Answers to Tosfos' Question