Do the laws of Shabbos preempt my choice of methods to protect my family in the case of a break-in or attack on my home on Shabbos? Also is the the use of a biometric safe to access the weapon something to consider. it it more favorable to use the key(which is a backup)?
Using the logic of pikuach nefesh, why would there be a restriction for any reason? If the most efficient means of protecting a life involves a gun, then it would be no different than driving a car to the hospital rather than waiting for the ambulance. I have heard rabbis and doctors refer to someone who insisted on walking to the doctor (or the rav for a psak) to see if the matter was serious enough to drive to the emergency room as "chasid shoteh". This would seem to be a similar matter.
If it was not serious enough to require a gun in the first place, it would not have been allowed to use the gun on a weekday. The reason being that one uses the gun only when it would be necessary to take the life of the attacker.
'Do not draw your weapon unless you are ready to use it to kill" is a piece of advice given in both fiction and real life.
Consider the case of a policeman who shot an attacker four times in the body and failed to stop him until a bullet hit the assailant in the head (killing him). (This is an actual recent case that happened).
Shooting to miss may deter the attacker, but the bullet could hit an innocent bystander. Even if the attacker is scared away, you need to be ready to act if he is not stopped.
Note that the Torah explicitly allows a person to kill a home invader unless "it is clear as day" that the invader is not a danger. For example Self-Defense or Law and Order Parashat Mishpatim (Exodus 21:1 - 24:18)
"ba ba-machteret," actually states that this is not a matter of "Pikuach Nefesh" but it is a case of rodef and the homeowner is in effect an agent of bais din carrying out a sentence of death that the invader has drawn upon himself. However, this would not prevent the homeowner from using his gun on Shabbos.
We read in Parashat Mishpatim the law of "ba ba-machteret," a special provision concerning a thief breaking into a house: "If the thief is seized while tunneling, and he is beaten to death, there is no bloodguilt for him" (22:1). Rashi, based on the Gemara in Masekhet Sanhedrin (62), explains that a thief breaking into a home may be killed. The Gemara bases this halakha on the principle of, "ein adam ma'amid atzmo al mamono" - we assume that a person will attempt to protect his property against intruders. By extension, then, we assume that the thief anticipates confrontation with the homeowner and is prepared to kill him. This assumption renders the burglar a "rodef," a "pursuer," attempting to kill, in which case others may come kill him to defend the intended victim.
Later in Masekhet Sanhedrin (72b), the Gemara observes that this verse does not specify who kills the burglar. The verse rather says simply, "ve-huka" - the thief is beaten to death. There is no indication in this verse as to whether it was the homeowner or a third party who killed the intruder. The Gemara derives from this ambiguity that anybody may kill the thief, not only the homeowner, whom we presume the burglar is prepared to kill. The Gemara explains that were it not for this textual indication, we would have limited this provision to the homeowner, and have forbidden the killing of this intruder by any outsider.
Why is this so? Once we have determined intent to kill, thus inviting the application of the standard halakha of rodef, why would we restrict this license to kill? Generally, anyone may and in fact should kill the rodef, the pursuer. Why should this case be any different?
Rav Avraham Yitzchak Sorotzkin, in his "Gevurat Yitzchak," answers by carefully dissecting this halakha of rodef. What precisely entitles someone to kill a pursuer? Rav Chayim Brisker (in Hilkhot Rotzei'ach) argues that the interest in saving the victim's life itself does not provide sufficient grounds to allow killing the pursuer. This is due to a principle in halakha called, "ein dochin nefesh mipenei nefesh" - we may not discard one life in favor of another. In a rodef situation, one person will be killed; either the intended victim or the pursuer. We do not have the right to make this decision. What produces the license to kill the pursuer is a different notion - a "chiyuv mita" (death sentence) issued by the Torah upon him. The Torah legislates that one pursuing another to kill him deserves to be killed. This entitles - and in fact obligates - onlookers to intervene and kill the pursuer.
In certain situations, a person may technically attempt to kill another but will not have a chiyuv mita issued against him. Rav Sorotzkin suggests that one could have viewed the case of ba ba-machteret as such an example. The burglar has not broken into the house to kill; he wants to steal money, not to take a life. Thus, although technically he might be deemed a pursuer, in that he is prepared to kill, one could have argued that no chiyuv mita can be applied in this case, since his primary intent is not to kill.
This, Rav Sorotzkin explains, answers our original question. Before extracting from the verse the permission for all people to kill the burglar, one would have thought that he does notbear a chiyuv mita. As such, the principle of "ein dochin nefesh mipenei nefesh" would prevent the license to kill the ba ba-machteret. Only the homeowner, who is himself threatened, would have the right to kill the burglar because of a separate halakha sanctioning killing in self defense: "Ha-ba le-horgecha hashkem ve-horgo" ("Someone who comes to kill you - arise and kill him"). Therefore, only once the verse informs us otherwise can we extend the license to all people, besides the intended victim himself.
Yesterday we discussed the halakha of "ba ba-machteret," introduced in Parashat Mishpatim, by which we assume that a burglar breaking into a home is prepared to kill the homeowner should he attempt to resist the theft. This then activates the halakha of "rodef," which allows for the killing of anyone attempting to himself kill another person.
Although the Gemara clearly classifies the ba ba-machteret under the general category of rodef, an important distinction between the two arises from the writings of the Rambam. In presenting the standard halakha of rodef, the Rambam (Hilkhot Rotzei'ach 1:6) describes it as a mitzva for onlookers to come to the aid of the intended victim and kill the assailant. By contrast, when the Rambam introduces the halakha of ba ba-machteret (Hilkhot Geneiva 9:7), he writes that people have permission to kill the burglar, mentioning nothing about a mitzva or obligation.
Why does the Rambam distinguish between ba ba-machteret and rodef, if the Gemara explicitly describes the former as an instance of the latter?
The answer seems to lie in the two-step process involved in the provision of rodef. Apparently, according to the Rambam, this halakha itself does not introduce any mitzva to kill the pursuer. Rather, the halakha of rodef merely sanctions this killing. This is the first stage. Once the Torah permits onlookers to kill the rodef, the general mitzva of saving lives now requires that they do so; once one is given an opportunity to save someone's life, he bears an obligation to do so. But this obligation stems not from the concept of rodef, but rather from the general mitzva of saving lives. The concept of rodef merely "sets the stage" for this obligation to take effect, by permitting the killing of the assailant.
In the case of ba ba-machteret, however, we do not reach this second stage. Recall that this institution stems from our assumption that a person will attempt to forcefully resist the theft of his property. This yields a second assumption, that the burglar, aware of this human tendency, is prepared to kill the homeowner should he attempt to resist the burglary. In most situations, however, the homeowner can easily save his life by remaining passive and allowing the thief to take whatever property he wants. Given that his life is not actually in immediate danger, the mitzva to save his life obviously cannot take effect. Only the rule of rodef applies, by which the burglar brings upon himself a chiyuv mita (death sentence) which allows other people to kill him. No mitzva, however, is involved in this killing.