obviously after u engage in convo with her and shit.... but does that line indicate 'lets just be friends'?

i use that if im unsure on a girl n if she would be comfortable with me outside of that conversation...

i think its better to direct something like

if your talking about some bar/club/ amusement park whatever be like oh we should go to ________

see how she reacts but let it be like part of the conversation rather then outside of it, that way later you can use it to go hang with her

I think you should be more leading with this... I would say...

"We should grab lunch sometime."
"Yeah, we should!."
"Good. Tuesday?"
"Works for me."

Saying, "We should hangout sometime" usually indicates to a girl that it is okay to bring a friend along.. which they usually always do because you're a stranger right? And what are you guys going to do hanging out 1 on 1? The vibe is already conflicting itself, because she doesn't have an idea what your intentions are. If you ask to go out to lunch with her, however, its casual and non threatening because it is during the day and signifies that you're not desperate, however, you're asking her to hang out 1 on 1 so you are indeed indicating that you are interested. Lunch is the perfect time to test the waters. Once she accepts, the real game is on, so don't worry about getting stuck in the friends zone until you're hanging out one on one with her. But be direct about it, so she doesn't end up flaking or bringing her friends along.