Offer help.

The man greatfully accepts your assistance, but cuts through all your attempts at apology in his desperation to be heard. "I'll - I'll hold them off", he spits through the pain, "just - just take it, before they get here".

No sooner is he back on his feet than he staggers off into the gloom, rejecting all further offers of help.

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.

Leave the painting where it is and continue your journey back to your hotel.

Pick up the painting and run like hell in the opposite direction.