I am not sure if this is just a bug on Stadia or if you can't do this at the moment. I wanted to ask before I filed feedback that you should be able to do this. On Stadia, I tried to dip my weapon into a torch one of my party members is holding, but was not able to do this. I could dip it into a torch which was nearby with no problem. Has anyone else tried to use their party members torches as a fire source? Were you able to do it? It would seem logical that your own torches could just as easily be used as a fire source as one attached to a wall, right?