I trained my guys to load up themselves. That way I have a straight escape out if they do freak. So I'll flip the lead over their back, tell them "load up" then follow behind to close the divider.
Then go out and around and clip on the quick release trailer strap
From the window.
We NEVER tie them with their leads. Well either loop the leads around their necks or toss them over their backs.
Then to unload we go reverse order. Unclip the tie, go open the divider and they're trained to back SLOWLY when we cluck or pull their tails