1- Parents cannot force their children to pursue a specific career.
2- At the same time, children should do their best to not upset their parents.
3- If you really are not interested in pursuing medical school, you are not obligated to do so. However, you have to be creative and soften their heart. Talk to them and make them realize that you have no interest. Let family members talk to them. Let family friends whom they respect talk talk to them. Let your counselor talk to them. Have all these people explain to them that if someone has no interest in pursuing a field, then one won’t be as successful pursuing it.
In the end, it is your choice. Islamically they cannot force you to pursue a career you don’t like. Just do your best to “mitigate” the damage and reduce their disappointment.