If you have a legitimate complaint about a proctor issue such as actually be shorted time for a section, file a formal complaint with LSAC according to the procedures.
If the proctor was a little bit off on when the five minute warning was given but 35 minutes was still allowed for the section you have no basis for a complaint. You are allowed to bring a watch to keep time yourself.
If the proctor keeping time in the room did actually mess up and short the room of the full 35 minutes for a section, that is a different story. LSAC investigates every formal test center problem/complaint including communicating with the proctor(s) about what happened. If several students that were in the same room submit formal complaints about time being called early and/or if the proctor(s) admit to LSAC they messed up then you probably will be offered a remedy. If just one student complains and the proctor(s) deny it, then most likely you will be SOL.
Keep in mind, as described below in the LSAC policy, if you file a formal written test center complaint, your score will be put on hold pending the investigation. That means that if you decide to just keep the score, if that is an option (meaning they don’t invalidate the scores of everyone that took it in that room due to determining there was a serious test center problem), your score will most likely be released later than normal release by days or perhaps a week or more.
The typical remedy LSAC has been offering in the past for insignificant/minor test center issues/legitimate complaints if they determine there was in fact one is to offer you a free re-take at a later administration if you opt to cancel and/or give you the option to just keep the score.
Also FYI, the proctors have to go through and do much more paperwork and fill out many more forms than test takers. Their job involves much more than just sitting there keeping an eye on a clock and calling time for the sections.
http://www.lsac.org/policies/test-center-problem-policies.asp
Policies Related to Test Center Problems/Complaints
LSAC administers the LSAT at hundreds of locations around the world. Although LSAC staff and local test supervisors (who are not LSAC employees) make every effort to provide a suitable test-taking environment, LSAC cannot guarantee that conditions will be optimal at all testing sites. In no case will LSAC be held responsible for test-center conditions beyond its control. If you encounter a problem during the test administration, report it to the test center supervisor; however, informing the test center supervisor is not sufficient. You must also follow up your complaint by writing with your signature to:
LSAC
662 Penn Street
PO BOX 2000-T
Newtown, PA 18940
USA
Fax: 215.968.1277
E-mail: > LSACinfo@LSAC.org
Your complaint must be received by LSAC within six calendar days after the administration via fax, letter, or e-mail. It is your responsibility to keep proof of LSAC’s receipt of your complaint (i.e., a fax transmittal report); however, no such proof will be accepted beyond 14 calendar days after the test. Indicate “Test Center Complaint” in the subject line and include your name, address, LSAC account number, the last four digits of your Social Security/Social Insurance number, the test center name, and the building or room in which you were tested, if known. Be aware that the availability of your LSAT score may be delayed pending the review of your complaint.