Can I sue a BART Transit Information Clerk for physically grabbing/pushing me out...

[Praki]

...for sneaking onto bart? I was heading into bart at the Daly City station and snuck in through the handicap/emergency/authorized door (which swings open) while the clerk was looking away...next thing you know he follows me up the stairs to the boarding area and tells me i have to exit the station..i said i was waiting for a friend and he just kept saying i have to go but i refused and stood my ground...he then grabbed my arm and pushed me as i was walking down the stairs nearly falling...i didn't fight back and told him to stop touching me but he kept shoving me out...he didn't even say he was gonna call the cops or security...i went to go buy a ticket and re-entered the station as he watched me...i am now looking up online about BART laws but can't find anything relating to my situation...i am now wondering if i can/cannot sue him since i snuck into the bart (which i could have gotten in trouble for in the first place)...Isn't it the bart security/police's job to escort me out? Did he have the discretion to put his hands on me? . i don't know much about the BART laws and would really appreciate ANYONE who can help, lawyers preferably....THANKS!!!