This phrase combines a polite suggestion with a logical reason to create a natural, gentle call to action.
The particle 吧 (ba) softens the phrase — it turns a blunt directive into a shared invitation.
The logical justification — time is running out, which prevents you from sounding pushy.
Core Philosophy: Chinese interpersonal logic relies heavily on "softening" suggestions. By combining a gentle invitation with an objective reason, you nudge people to move without creating social pressure.
Dropping 吧 (ba) turns "我们走" into a direct order. Adding 吧 softens it into a polite invitation.
The pattern 要 ... 了 (yào ... le) means "about to happen."