AT ABOUT two o'clock in the morning last week, my roommate called the student escort service. She had been working late in the Square and was feeling a bit uncomfortable about making the ten minute walk to her home, which is in between Harvard and Central Squares.

When she told the escort service operator the address of her apartment, which she had subletted for the summer, the operator only wanted to know, "Is that a Harvard building?"

When my roommate replied in the negative, the operator barked, "Harvard building to Harvard building only."

So she headed off for home alone and at her corner, a man standing in a darkened doorway, leered at her and exposed himself to her.

INSTANCES LIKE THESE are rare, but not as rare as some people would like to think. Ironically, my roommate had sought to follow the advice of crime prevention officers by taking steps to protect herself. But because of one major flaw in the otherwise beneficial escort service, she was verbally assaulted and ran a risk of being sexually assaulted.

A service formed more than 10 years ago as part of a crime prevention program, the student escort service is in theory, an excellent idea, but there is a catch. Although students are relatively safe while travelling between the river houses and the Yard, mostly because of the campus police, walking farther distances late at night can be more than a little risky. Massachusetts Ave. can be rowdy, to say the least, and alternate routes are often dark and deserted.

Unfortunately, the escort service does not, as my roommate's story and many others like it prove, serve its true purpose: protecting Harvard students. As the program operates currently, it protects only Harvard from being responsible for incidents that occur on University property.

Strangely enough, the student escort service will accomodate students going to Harvard-owned buildings which are farther away than some non-Harvard owned buildings. During the year, this policy operates primarily against the small percentage of students who are live in non-Harvard housing. But during the summer more than half of the students in Cambridge do not live on campus and of those a substantial number do not live in Harvard housing.

And how about all the students working for Harvard in the summer who must work late and who also may not have had the fortune to find Harvard Real Estate housing? Students who work in the Biological Laboratories, for instance, must go home through a dark and deserted area and face a greater risk than students travelling along Mass Ave.

These are the students for whom the escort service should have been created. These are the students who face the greatest risk in walking home alone late at night. Crime prevention officers caution against people travelling alone, yet with the present escort service some have few other options.

Police officials say that the service operates on a case-by-case basis and that if a call comes in late at night, asking for a ride of a reasonable distance, the service will oblige. But this did not hapen last week when my roommate was refused a ride by an operator who, no doubt, was just doing her job.

BETWEEN THE TIME of 7 p.m. and 3 a.m.--when the service is operating--there is only one car available. The Harvard building to Harvard building policy helps insure that students do not have to wait too long for a car. Yet it also discriminates against those people who do not live on campus.

One policy change that might solve this problem would be to establish a region in which the escort service would travel no matter where it was going.

With this change, all students could benefit from the service and an operator would not tell students at two in the morning that they have to walk home alone because they do not have the right address.