Hmm, thinking about it, I think you're right and this just hadn't come up in testing. My intuition would be that technically the movement of either traveller stops after just one move when they're right next to each other like that, so placing a neutral gate in such a circumstance shouldn't be allowed; I'll need to adjust the rules to include this case. Thank you!
It did seem during testing that crashing-related victories were the norm and actually getting to the goal was more of a "this'll happen eventually if you don't act" -type timer for gameplay; it's not quite what I had in mind with the design but it did still lead to fairly interesting gameplay during testing so I thought it'd be ok for the nature of the game to be more crashing-oriented. Was the simultaneous crash issue the main problem when you were playing, or do you feel that even with the above adjustment the game would end in a similar situation too easily?