Whew. That was a long and exhausting plane flight. About 15 hrs. 

Anyway, I'm with Org on this one. The smart thing would be to run for now and come back on a battlefield of your own choosing. Although Chres would welcome the chance of getting himself killed in a humiliating way like this, the bodyguard in him feels an obligation to make sure his death won't be a serious detriment to the team. 

The cult did mention that they would rather have the characters alive than dead due to something Ms Sightless referred to as the Unspoken Pact. That may give us somewhat of an edge in a fight, but the numbers are on their side. Also there are ways to injure and immobilize people without killing them. Keep in mind that our new friend never said keeping our characters alive was a requirement. So it might not be too much of an edge. Also they have magic users and deterrents. A hasty escape is by far the better option than an unprepared and uncoordinated strike. 

Also running away in a situation like this isn't guaranteed to be clean. We are surrounded. Even with illusions helping us, one way or another our characters are likely to be spotted escaping, especially by the Sightless. Sightless can't see light, and since light constructs are made of light, she'll be the first to notice what's going on. 

So although we might not get a chance to kill a sightless just yet, her spotting us almost guarantees that our characters will have to duke it out with her before escaping. The ability for her to grow her appendages will make it easy for her to reach the rooftops and what not. Since her fellow cultists can't do the same, this will also give us a numbers advantage against her.