Lets just say this event was not well thought-out. The coil is a unique activity, in that you run a total of FOUR "paths" and visit Riven to purchase activity boons before each path, including Revive Tokens. The new portal system includes an "extinction" modifier which removes all revive tokens... and also has penalties for going over the allotted time, such as removing all the revive tokens when the clock runs out. My guess is that you joined a match-made Coil run where one of these mods were active, but the game still allowed you to buy revive tokens despite them being disabled. Another nonsensical note about the coil : Even if you have zero revive tokens, and someone dies in the middle of a "path"... they will automatically respawn if one (or both) of the other players is able to complete the path & "pull" them to the Riven room.