Run back.

The man you knocked down is struggling to his feet, holding his leg and grimacing in pain. He sees you and your pursuers racing towards him, and points to a wall where a painting stands wrapped in brown paper.

"Take it to Aveugle", he groans, "I'll hold them off."

You can:

Grab the painting and run like hell.

Forget about the painting and flee.

Stand alongside the stranger and tackle the hoods with him.