Why did she carry extra tape on her uniform?

Nancy carried extra tape for added protection. The evidence below comes directly from the text.

"She found a box of latex rubber surgical gloves and a plastic shaker full of baby powder. She shook baby powder onto her hands and pulled on the gloves. Then she found a roll of sticky tape, and she tore off several strips of tape and hung them in a row on the edge of the desk.

Then she taped herself. Taking up one strip at a time, she taped the cuffs of her gloves to the sleeves of her scrub shirt, running the tape around the cuff to make a seal. She then tapped her socks to her trousers. Now she wore one layer of protection between herself and the replicative Other."