it took me 24 hours to figure it out, but i finally realized what i should have said to the guy on the metro:

scary military man trying to subjugate me: "if you push me again, i will punch you.... stupid bitch."

second year law student (me): "if you touch me, i will sue you for everything you own."

i normally confront hecklers because i know the law is on my side... in this situation, i temporarily forgot that the threat of the law is pretty powerful as well.