Through an air duct

The front door would be far too obvious, and stealth is the name of the game, so she elected to try an air duct she had located earlier.

Starlight sprinted across towards the building, dropping to her knee's before a metal grille about a foot off the ground. She glanced around to ensure that she was totally alone before reaching into the loose belt that hung about her waist and producing a simple multi-tool, flicking open a screw attachment and setting to work on the grille.

She could easily have ripped it from the brickwork, or else cut through by focusing her light powers into a concentrated beam, but there were times where the simplest approaches where the best, and this would raise far less questions come the morning.

It took about a minute before the last screw popped loose and clattered onto the pavement, allowing the grille to simply slide free of the bricks with a soft grating noise and leaving an opening just large enough for a person to clamber into.

Starlight took a moment for a final stretch before sliding her booted feet in, and shimmying her way in. She paused for a moment to reach out and pull the grate back in place, to avoid arousing any suspicion, before crawling back through the duct, searching for an exit.

She tried to move as silently as possible, but was still painfully aware that every movement produced noise that reverberated and echoed around her in the metal passageway. Gritting her teeth and praying that there was nobody around to hear her, she pressed on as best she could, crawling around for several minutes yet finding no opening of any kind.

Based on her mental map, she should have covered the width and length of the building by now, but found not a single opening out into any of the ground floor rooms, how curious. What was the point of an air duct that didn't lead to any of your rooms? Her question was answered a moment later as she felt the metal beneath her begin to slope downwards, so there were rooms beneath the building...

Excited by her discovery, Starlight pressed on with haste, following the slope downwards as it increased in gradient. Soon it was all she could do to keep in control, so great was the angle, and she began to consider turning back and looking for another way in. Before she could act on this though, she took one step too far and felt her hand plunge into a void where she had expected to find a panel. Unbalanced, she was helpless to stop herself as she toppled forwards, losing all sense of control and slipping along the slick metal of the duct, skidding downwards at speed.

She bit back on a scream as she feel, reaching out and trying to brace herself against the walls, slowly bringing her descent back under control until she hung, panting, in a vertical section of the shaft. She let out a shuddering breath and glanced upwards into the inky blackness of the shaft, estimating how far she had fallen. Far further than she had expected. Below her though was a tiny glimmer of light, another grille! Smiling to herself, Starlight slowly began her descent again, taking her time to avoid any further slip ups.

A few minutes later she was kicking the grille from its mountings, and dropping gracefully into the darkened room below.

The faint light she had spotted was coming from underneath a doorway over on her left, the rest of the room was near pitch black, though she could easily change that with her abilities. The question is, should she stay put and explore her new surroundings, or just rush onwards and see what lays beyond that door?