That is pretty odd. I don't think that is an issue with the game. If it were, 'twould most likely crash automatically if the computer had an issue with the map files.
'Ave ye tested 'nother map like Flourite, running 'round to see if ye crash like ye do in Ficho Tunnel?
How is y'er internet connection? It may just be y'er internet 'aving difficulties with the Ficho Tunnel map server. Each map has its own, f'er lack of better words, server that connects everyone to the map.