Missed opportunity (38M) (35F)

Here’s the story:

Woman works at my pharmacy and always chats with me. I never sought anything other than being friendly as I was in my previous relationship at the time she worked there.

The store encounters some issues with staff and she quit. I never saw her there again.

Went to a flu shot clinic. Sat down and I was staring at her. It was different. So happy to see each other. We started talking and catching up. Got my shot, said see you later and went home. Instant regret that I didn’t ask her number.

I know where she works but it’s a private research like facility that I would not be able to enter as a visitor. I’ve also looked on all SM platforms online, hours on Google, she does not maintain any online presence.

How can I get in touch with her to ask her out? I only know these few details and I haven’t come up with a way to contact her. I’d love suggestions.