To me it's similar to the English 'Right, we're off' which you might say just before you actually set off ie. when the decision to leave immediately is seen as already having been taken (at least by the speaker).

Перешли мне, пожалуйста, его ещё раз. = Please send it to me once more.
This looks like it's from переслать(перешлю,..) rather than перейти.