I have an odd question...

I have a 4 hr. stopover in Narita and need to go to Tokyo to drop off a package for a friend.

I was thinking of taking the JR Narita Express train and meeting him somewhere in one of the stations and immediately going back to Narita to hop on my next flight.

My question is this - can I just pay the 3100 yen ticket, hand the package to him without going out of the station and hop right back on WITHOUT getting a "return ticket" back to NRT?

I don't mind paying the one way fare but it won't be worth it paying it twice for the package.

Analagous to taking something like the NYC subway where you can basically stay on the train all day long for 1 fare...