Hello and welcome.
I'll need a native to correct me if I'm wrong, but I'm pretty sure the simple answer is that
ir is not reflexive and it means to go.
Irse is reflexive and means to leave.
"Ustedes se van a la ofic
ina" would translate to something like: You (guys) leave
to the office.
Here is a more complicated answer:
http://www.spanishdict.com/answers/116091/ir-vs-irse
