"Wir sollten gehen" can be two things here: Past or subjunctive.
The first might occur in a narrative:
"Wir sollten ins Schlafzimmer gehen während Mutter den Weihnachtsbaum schmückte" (we should/ were ordered to go into the bedroom while mother decorated the christmas tree)
The second can either mean a suggestion:
"Wir sollten ins Schlafzimmer gehen bevor uns jemand sieht" (we should/ ought to go into the bedroom before someone sees us)
Or it can be induced by indirect speech (in this case past as well):
Er sagte, wir sollten ins Schlafzimmer gehen (he said we should go into the bedroom).
Sakasiru is correct about a better translation, but (if I'm not mistaken), you are correct that technically it can mean that as well. It just wouldn't normally be read or understood like that.
It's a rough analogy, but consider the phrase "I see the well." Sure, technically it could mean you do a very good job of seeing "the" (maybe you can read "the" more easily than any other word?), but nobody would read it like that. English speakers would all understand you as seeing something with a lot of water inside, and if you said "wir sollten ins Schlafzimmer gehen," Germans would understand you as using the subjunctive, not the imperfect.