I don't think they went 128 from RI. That time of night straight through Boston on 93 is the quickest.
Could be one of the cars came from the west, and they met up after the 93/95 junction.
Also, I don't think there are any gas stations/eats right on 128 or 93/95 in MA. You have to exit. Places are right off the highway, so no big deal, but it still is a PITA. The 93 route is definitely a no get off road, though, IMO. Hold it until you get to 95.
Anybody in the breakdown lane on those roads in MA is going to have the staties on them pretty quick, too. Should have known that.
Agree it doesn't sound right. Pit stop to pee is the most likely, because I think they went 93, with maybe another car from the west needing some gas at the meet up.