I didn't think they were losing ground at all, they are doing what they have done since the beginning, challenging the witness, attacking the "confirmation bias", etc. He was challenging him on the reflection off the latch thing... and McGee made some good points, there were 2 other latches on the side of the truck, one in the same position, another one turned another way, why didn't they reflect whatever the other latch was reflecting? Why wasn't there a reflection off the passenger window? or the side mirror? Why wasn't the fire hydrant showing a reflection of the same light? or the manhole in the street? When Liscio said maybe a physicist could answer that... well...