Education Lab is a Seattle Times project that spotlights promising approaches to persistent challenges in public education. The Seattle Foundation serves as the fiscal sponsor for Education Lab, which is supported by grants from the Gates Foundation and Ballmer Group. Learn more about Ed Lab and subscribe to our weekly newsletter . SEATAC — The rumble of the light rail arrives in waves at The Roadhouse, a low hiss and metallic rush that slips through the open doors beneath the Angle Lake Station platform. Inside, the venue feels more like a living room than a transit stop: couches gathered in front of a small stage, lights casting a soft purple glow from below and yellow from above. Students drift in before instructor Alex Wren calls them into a semicircle.  “I like to call this ‘brain files unlock,’ ” Wren tells them, asking students to share what they remember from the previous session.…