You’ve taken a defensible position. A Singularity is blocking the side doorway to keep you from getting flanked. Everyone is ready to turn the street ahead into a veritable killzone as soon as the enemy comes around the corner.
And then your friend zips halfway across the battlefield in a burst of blue light like Leroy Jenkins and you’re all left sitting there going, “Umm… so… should we run after her?”
Don’t panic! Everything is going to be fine. You’re just experiencing a common condition known to the BioWare Dev Team as “Someone’s Playing a Vanguard.” And we can help you through it.