Being first is not always an option but sometimes it is required. If that can't be done then one has to consider other ways of completing what one has started. If that requires letting somebody else go first - then so be it. If that is so then it needs to be someone you can trust to mind the shop as it were.
However if that fellow starts a discussion concerning the obscure use and application of harnesses then it is time to look him squarely in the eye. The first instinct would be to question him. That would be wrong. There is only one course of action and that would be to call his bluff.
As with any bluff the safest strategy is not to follow too closely.
Caution at times needs to be thrown to the wind.