<modsnip> He's primarily not there to argue with them (my claim vs yours). Instead, he wants the guy to commit to specifics, and he focuses on places where the vagueness and assumptions and the transparent stupidity lingers. Alessi was nailing him down to commit to this or that (If you listen, he's asking "Is that your testimony?" and working to get that question answered, in this point or that.).
When W said that "an arm would break the taillight if the car was traveling at over 8 mph", with no actual tests, and something that doesn't pass the sniff test for anyone who has ever jogged past a car, Alessi doesn't want to mess with that. Just mark it. The ball is positioned perfectly on the tee.
Let the cw rest its case, which locks in their experts' claims. THEN bring the def experts to knock the stuffing out of the stupidity on display by this one claiming to be an expert, claiming to have integrity, claiming he's not making stuff up to pad a weak-to-nonexistent case.
The same was true with the 1162 nonsense that you and others crowed about, when def didn't challenge it in the moment. They left his nonsense right there on the tee, and then let the later cw witness be dismissive of the idea (which happened) and then left the ball on the tee again for the def experts to smash to smithereens. They're coming.
Why would Alessi challenge it and push for something better? For the def, that testimony was PERFECT.