Ok..so where the SA is going with this line of questioning (IMHO) is that the levels of chloroform were so high...even with a clean up of the trunk after the fact...that those levels of chloroform are SO HIGH that a clean up would not explain them. But the fact that JA got the witness to admit (before JB objected to the two part question deal) that the stains were of human origin is huge. I get that the DT has coached their witness, but still, he admitted it under oath before the objection.
PS we all now know that the A's don't use stuff in their pool that would comprise those levels. Hence, drowning by accident is void for the defense.