Lyric discussion by boosh18 

Cover art for 50 Minutes lyrics by Robots in Disguise

To me it sounds like she's saying it as a progression:

50 minutes ---> 52 Weeks ---> 4 years

like the relationship went so quickly, but in reality it lasted 4 years. Which makes the bit when they both sing together saying 50 minutes 52 weeks 4 YEARS!

i don't know whether i'm explaining this correctly! Like 50 minutes of relationship went by, then 52 weeks and finally 4 years and then it ended

it makes sense to me!

that makes perfect sense to me.