Fold a cloth into a tight package or a ball, place it on the underside of her arm, continue holding with the towel. Glass is easy to remove, just don't move her arm much.

[ He's certain if it was life threatening Jo would say so. ]

Don't fuss with the glass, just be calm. There's a doctor making her rounds - I'll send her over, I need to sweep through the town, make sure no one is dying. I'll check on your mother as soon as that's done.

[ Triage. ]