Man, I thought I was the only one who did that trick, Meryl.
Everybody on the Neoseeker GTA3 forum was all "Ya gotta get a tank, set up a roadblock..." or "You have to get an Infernus and drive it through the tunnel in 1st person view.. that's the only way". I was all "..hello? Subway? No traffic?"
Also.. did you guys find the "1st person view" to be more of a strapped-to-the-bumper view than one from actually driving the car? They should have shown the steering wheel turning & stuff.. would have helped gameplay in that department, I think.