What is the ruling on a Muslim woman studying in a coeducational university?

The questioner: His EminenceThe Shaykh- May Allah reward you - Is it permissible for a committed girl to study in a coeducational university on the grounds that she is committed to the Shari'ah hijab, and that she sits in a separate seat or chair, slightly away from the male students, and on the grounds that she calls her female peers to the da'wah to Allah and to adhering to it, and there is no harm in reminding them that most faculties do not benefit from studying in them, such as the faculties of law, agriculture, engineering, and the like - and may Allah reward you with good -?

The Shaykh: May Allah reward you; this question is like other questions that fall under a non-Islamic rule: "The end justifies the means." This woman wants to study in a university where young men and young women mix; for what purpose? In order to call to Islam, to learn and call to Islam. So the previous point returns: she is burning herself in order to benefit others. She commits Shari'ah violations for which there is no justification for committing these violations; because seeking knowledge in universities today, the original ruling is that it is not an individual obligation (fard 'ayn) upon her, even if one looks away from some of the things that are not on the level of an individual obligation. And everything said about this being a collective obligation (fard kifayah) that falls off the rest if some people perform it, but despite that, I think thatThe student : the students today study in universities sciences whose harm is greater than their benefit, so how can this be taken as a means to call to Islam?
Please proceed.