^^ Cold will not reduce Dyneema strength. Commercial fishing
uses this routinely in very cold water
. Though sub-zero with stiffen it and could cause trouble, it will not hurt it unless stressed at the same time.
Though I have posted many times on energy absorption, and have ocasionally criticized Dyneema for tethers, a tether this short will not generate dangerous forces because the human body will deform, easily absorbing them. Climbers have proven this. It is ONLY when the tethers reach ~ 2' (pure vertical drop against rigid anchor
point-->4' fr horizontal throws) that the danger
becomes real. For a 1' tether there is no impact risk, and the stretch of nylon webbing would not amount to much.