First of all, you need to understand that getting a medical call does not mean that final decision has been made on your file by a visa officer. It means that you are eligible for the next phase. Your file is complete, will be reviewed and concluded by the visa officer. Common sense suggests that withdraw chunks of money only when you have a visa stamped passport in your hands. Otherwise, wait patiently and hope for the best.
What if a visa officer calls your bank and there is a discrepancy in your bank records and it falls below a required level then you already know what will happen?