No need for finesse, brute should work

"There shouldn't be a lock," Ha'Penny explained, examining the blueprints again, "It should just swing open?"

"Maybe it's just stuck?" Jane said, pushing harder against the vent cover.

The cover refused to budge, so she pushed harder. Then she pushed harder again. Then she slammed her shoulder against the impenetrable barrier.

CRACK!

"Eeek!" Jane yelped as the vent cover burst open and she tumbled through the opening.

SNAG!

"AAAAAH!" she whimpered as her panties snagged on the metal edge and she ended up dangling by her underwear above the corridor below. "Ow! Ow! Ow!"

Through watering eyes, the wedgied Jane glanced back and forth. Thankfully the hallway was empty. Unfortunately, she was dangling a dozen feet above the ground.

RIP!

THUD!

"Ugh!" Jane grunted as her panties tore in half and she slammed into the concrete floor.

For a moment the spy lay still in just her bra and bracelets with her legs spread and stars dancing around her head.

"Agent Jane?" Ha'Penny called.

"Uh... Wha?" Jane groaned before lifting her head and rubbing the red bump on her forehead, "I'm alright!"

Struggling to her feet, Jane blushed as she looked down at her bare privates and exposed bottom. Her attention turned to the torn scraps of her panties, still suspended from the air vent high above.

Even if the ripped fabric were still wearable, it was well out of reach.

"I just have to avoid being seen!" Jane reminded herself as she hurried along the corridor, her ample breasts bouncing as she held both hands in front of her neatly trimmed privates. "I'm a super spy! I can do this!"

Following the signs to the main research laboratory, Jane was almost there when she spotted a shadow moving around the corner ahead of her.

"Hide!" Jane whispered, darting toward a pair of large, potted plants and holding the leaves in front of her for cover.

Peeking between two leaves, she spotted an elderly janitor wearing glasses as he walked around the corner, pushing a cart.

She held her breath as he approached. Her heart was racing as he stopped right in front of the two potted plants and turned toward her.