How long do you wait when opponent has paused?

I've been waiting like ten minutes with my opponent paused, no "sec" or "phone" message to clue me in on what's going on. Sent a message to ask if everything is ok, no reply. Are they just waiting for me to quit the game, and if so, at what point is it acceptable to just unpause and go kill their TC if they've gone AFK? I don't want to take a cheap shot but I don't want to just quit and lose the game if they're trying to stall me out.