Most people places a coin outside pap/krex portals to let others know not to enter and potentially wasting a run, however there are still others who either forgets or do not know about it. I suggest having a popup when entering boss portals to warn you if there is someone already inside but has not yet spawned the boss, something like "There is currently somebody already inside, would you still like to enter?", with the IGNs of the people inside. For krexel, i find that its a waste of time climbing up krexel entrance only to realise that somebody is inside. My suggestion for krexel is to have a NPC below that you can click on to see if the boss has already started.
Have the two 'light bulbs' on the entrance to pap turn red when there's somebody inside but it hasn't yet been summoned (doors locked). Simple fix. Unsure about Krex tho edit: The yellow bulbs turn red on each side
its a good idea, but its kind of funny to run into another party at pap and i met a friend in this way. i like when people handle these issues themself but would support a 'warning' , y not.
If I'm not mistaken the magic circle around the clock above the entrance disappears when someone has already entered the Papu map. Any GM to confirm this? (This indicator worked for me up untill now)