Verified answer

he said it will drag the process on and make dims look dumber

Mike Pence is the killer eitness. In a criminal case, he would be called to testify. He can't plead the fifth, because he isn't on trial.

Lindsey is an opportunist and maybe his motive is more personal than political.  For all we know Lindsey may be miffed because of the wording of Moscow Mitch's email regarding voting for acquittal. Maybe Lindsey thinks that by throwing a spanner in the works it prevents the senate from confirming Biden appointments and proceeding with the Biden legislation thus keeping him in Trump's good graces.