I would say that the most logical explanation is that he expected the fog to act as some kind of reference to his altitude. Fog has a nasty habit of changing quickly and disorienting jumpers who pass though it. The biggest mistake was that neither Erich nor Lunder planned a timed delay, but instead were relying on Erich to reach for his pilot chute. That was Lunder's signal to pull. Any lower and we might have had two fatalities.
Lunder actually saw Erich hit the ground. He attempted CPR but realized that Erich's neck had broken after attempting to tilt back the head. I haven't asked much more of him since the memorial service.
Not wishing to rain on your parade, LOL!, but you run into "all kinds" of folks here at FReerepublic!
Having said that, let me educate you about what happens to the human form that slams into the ground at 120mph plus!
Ya see, I have scooped up whats left of 3 souls after they #1: fell off a biplane during an air show, and, #2: their shoots (both primary, and reserve) failed!
Trust me Bubba...Lunder wouldn't have had to "tilt the head back" to realize the laddy was abit outta shape...if ya get my meaning...
When did FReerepublic start sending out confirmation emails???