At Vault Yoga, co-owners Patricia and Diane keep the stressors of the outside world at bay with an industrial-strength bank-vault door. A few years ago, Patricia, a former aerobics instructor, and Diana, who came to yoga after dusting off an old yoga VHS tape, fell head over heals for the healing postures. After they earned their 200-hour certifications, they started looking for a studio space that embodied the inner peace and physical strength yoga had brought them. After a lavender field filled with Mr. Universe contestants fell through, a century-old bank, complete with an old-timey vault, seemed just the ticket. Now, along with a team of instructors, the studio invites students of all abilities and experience levels to limber up in classes that range from gentle Yin fusion to rigorous Vinyasa flow.