Is it incumbent upon a physician who is not financially able to perform Hajj to apply for the lottery of the medical mission for Hajj, or to seek employment in Saudi Arabia in order to perform Hajj?

As long as you are unable to bear the expenses of Hajj, you are not considered capable. The stipulated capability is the possession of provisions and a ride. You are not obligated to seek employment or strive to join a medical mission to attain this capability, as acquiring it is not obligatory. However, if you enter the lottery for applicants to the medical mission in order to perform Hajj, that is good. It is recommended for one who is not obligated to perform Hajj to undertake it if possible, without incurring harm.