Is there issue of Yichud in an Elevator?

If your brother, your own mother’s son, or your son or daughter, or the wife of your bosom, or your closest friend entices you in secret, saying, “Come let us worship other gods”—whom neither you nor your ancestors have experienced —

MISHNA: A man may not be secluded with two women lest he sin with them, but one woman may be secluded with two men. Rabbi Shimon says: Even one man may be secluded with two women when his wife is with him, and in that situation he may even sleep in the same inn with two women, because his wife guards him from sinning with them. They further said that a man may be secluded with his mother, and with his daughter, and sleep alongside them with bodily contact without clothes, since there is no concern that they will engage in sexual intercourse. And when they, the son or daughter, have grown up, this one sleeps in her garment and that one sleeps in his garment, but they may share a bed. GEMARA: What is the reason that a man may not be secluded with two women, but a woman may be secluded with two men? The school of Eliyahu taught: Since women are of light mind they are more easily seduced. The Gemara asks: From where are these matters, that it is prohibited for a man to be secluded with women, derived? Rabbi Yoḥanan says in the name of Rabbi Yishmael: From where is there an allusion from the Written Torah to the prohibition against seclusion? As it is stated concerning one who incites others to idolatrous worship: “If your brother, the son of your mother, entices you” (Deuteronomy 13:7). Rabbi Yishmael considers why the Torah uses the example of “the son of your mother.” But is it only the son of a mother who entices? Doesn’t the son of a father entice? Rather, the verse means to say to you: A son may be secluded with his mother. Consequently, if a woman has two sons from two different husbands, they will both stay close to her. The Torah therefore uses the example of “the son of your mother” because half-brothers who share a mother become close to each other. By contrast, half-brothers who share a father will not become close, since one’s father’s wife who is not one’s mother is a forbidden relative. And it is prohibited to be secluded with those with whom relations are forbidden by the Torah.

It is forbidden to enter into privacy with any of the woman forbidden as ariot, even if she is elderly or a young girl, for this leads to forbidden relations. [The only] exceptions are a woman and her son, a father and his daughter, and a husband with his wife who is in the niddah state.
When a bridegroom's wife menstruates before he engages in relations with her, it is forbidden for him to enter into privacy with her. Instead, she should sleep among [other] women and he should sleep among [other] men. If they engaged in relations once and afterwards, she became impure, he is permitted to enter into privacy with her.

When the incident concerning Amnon and Tamar occurred, David and his court decreed a prohibition against entering into privacy with an unmarried woman. Although an unmarried woman is not an ervah, such an act is considered as entering into privacy with an ervah. Shammai and Hillel decreed a prohibition against entering into privacy with gentiles.
Thus when anyone enters into privacy with a woman, whether Jew or gentile, with whom such an act is forbidden, both the man and the woman are given stripes for rebellious conduct and an announcement is made concerning them. An exception is made with regard to a married woman. Although it is forbidden to enter into privacy with her, if one does enter into privacy with her, corporal punishment is not administered lest a rumor be initiated that she committed adultery. Thus a rumor might spread that her children are mamzerim.

It is forbidden to be secluded with a person with whom sexual relations are forbidden, whether elderly or young. This action leads to uncovering of nakedness. This law does not apply to a mother with her son, a father with his daughter, and a husband with his menstruant wife. A groom whose wife became niddah before consummation is forbidden to be secluded with her. Instead, she sleeps among the women and he sleeps among the men. But if he consummated the marriage and then she became [menstrually] impure, he is permitted to be secluded with her (see Yoreh Deah chapter 192). After the episode of Amnon and Tamar, David and his court forbade seclusion with an unmarried woman. Even if she is not forbidden as an "ervah" (person with whom sexual relations are forbidden), it is still considered as seclusion with a forbidden sexual partner. Shammai and Hillel forbade seclusion with idol-worshippers (non-Jews). Therefore, anyone who is in seclusion with a woman with whom seclusion is forbidden, whether Israelite or idol-worshipper, [the court] administers lashes of rebellion (makat mardut - Rabbinically sanctioned lashes) to both, the man and the woman, and the punishment is publicized. Note: [We administer lashes] only if it is known that he secluded with her, but her testimony alone is not sufficient [to convict him] (Rivash chapter 265). Even a single witness is not believed (Maharik root 189). Nevertheless, when the court has reason to believe that there was a transgression, it is necessary to separate them (Rivash ibid.). However, with a married woman, even though it is forbidden to be secluded with her, if one did so, they do not administer lashes so as not to spread rumors that she had relations (with him), which would lead to rumors that her children are mamzerim (the products of a sexually forbidden union). If his wife is with him, it is permitted to be secluded with any woman with whom seclusion is [usually] forbidden, since his wife guards him. But an Israelite woman may not seclude with an idol-worshipping male even if his wife is with him.