The 30 second rule would make a fine optional rule that could be applied occasionally, as a special (regional or match) rule. It just doesn't belong as part of the normal rules of the game.

On normal games, ones that haven't been expressly set to this "Speed Game" mode, there should be effectively no time limits at all. (If any time limit is in place, it needs to be long enough that it applies exclusively for knocking out AFK players, and doesn't apply to anyone who's actually playing TT. So set that to several minutes, but make exceeding it an automatic forfeit of the game. It should also be exclusive to PvP games, as there's no need or reason to protect NPCs from AFK players.)