You haven’t provided enough information to give a well rounded answer — but, generally speaking a qualifying pension can not be attached to settle a lawsuit while it remains within the retirement fund. Once removed from the fund safety net it is completely vulnerable to collection proceedings.
You may want to reconsider taking a lump sum distribution, unless you believe you will be finished with school before the suit is settled. But that is a little like gambling.
Finally, a word of caution — companies often have insurance policies that indemnify their employees from liability risk and attorney costs resulting from the employee’s agency status. Some companies try to shed liabilities to their employees by claiming the employee’s actions were outside the scope of employment. If you haven’t already done so, you should consult with your own attorney (not the company’s) to determine your potential liability and the quality of the defense representation from your employer.
This is not legal advice and is not intended to create an attorney-client relationship. You should speak to an attorney for further information.