Liz wasn't sure what Dr. Venkman was up to, but before walking into the shop she put out her cigarette. She slid through the door, taking in the site of the shop. She was a little surprised that the proprietor was blind, but the moment didn't last.
Since Dr. Venkman didn't step out of the way, Liz said behind him when he was done speaking, "I'm his employee, Liz Sherman."
There was no reason not to introduce herself as she saw it.