For me it’s both windows open, listening for screams or crunches, look out of window if jackknifed, but get on both the mirrors asap.
I reckon you’re better off facing forward and turning your head to both sides to keep more of an allround lookout.
I wouldn’t say anyone else is wrong, just what works for me. As always if in doubt about clearances get out n look. The best to learn is by doing: let the trainee loose and stand back, blow a whistle or give a shout if there’s danger otherwise give them time and space to make their mistakes and learn from them.
Sent from my GT-S7275R using Tapatalk