LOFT exercises are always the best form of simulator training as they come closest to reality.And always one subtle failure as opposed to a multitude of problems.No briefing either as you dont get one in reality.For example,imagine a flight from A to B with a go-around at B due to a blocked runway followed by radar vectors towards rising terrain(ATC error).The instructor should aim to challenge the crew's situational awareness at the least inopportune moment but never in a contrived manner.