Is traveling to non-Islamic countries such as "London" for the purpose of medical specialization and experience, and securing one's financial situation, with the intention of not settling there for long, considered unlawful (haram)?

It is permissible to travel to non-Muslim countries if there is a valid purpose or a recognized need, such as da'wah (inviting to Islam) or acquiring beneficial worldly knowledge that is not efficiently available elsewhere. This is conditional upon taking precautions against temptations, such as safeguarding oneself, avoiding evil, lowering one's gaze, minimizing corruption, and seeking righteous company. However, it is preferable to stay away from these countries and strive to develop oneself and seek beneficial knowledge in Muslim lands.