Correct him.

The man's eyes light up with relief. "Thank God!" he sighs, then hands you a painting wrapped in brown paper.

Approaching running footsteps distract him, and he glances over his shoulder. "There are two of them", he says, low, "armed with Bowie knives. I took one in the leg, it's better than it looks. You get the portrait to Aveugle, I'll lead them off."

With that, he hobbles away into the gloom.

You can:

Chase after him. He has a bad leg, he can't have got far.

Try to find some light so you can take a look at the painting.

Stand the painting against a wall and leave it there.

Run like hell anywhere but in the direction of Lee-eye-sester Square.

Judging by the man's limp, if his wounded leg is better than it looks then it must look absolutely ghastly...