Is it better for a female student to continue studying medicine despite her poor academic performance and her desire to devote herself to seeking Islamic knowledge, or to leave her studies and turn to seeking Islamic knowledge? Is it permissible for her to go to an institute to learn Islamic sciences without her parents' knowledge? And do her parents have the right to force her to stay in college?

In your situation, the preference depends on your ability to acquire religious knowledge and benefit from it, and whether your academic underachievement is genuine or an evasion from college. If you excel in religious knowledge and are capable of teaching and da'wah (proselytizing), then it is better for you to dedicate yourself to it if your academic level is truly weak. However, for someone who can combine both, that is preferable. For someone who can master her university studies while pleasing her parents and benefiting her nation, dedicating oneself to that is better after acquiring the obligatory religious knowledge. It is not permissible to leave for seeking religious knowledge without parental consent, except for learning obligatory knowledge. Obedience to parents is obligatory in remaining in college if there is a true benefit and purpose in doing so, and if you are capable of studying.