Not just refuse to vote, refuse to accept the referral from the House. I mean literally take no actions on the Articles of Impeachment. If you read the Constitution there is a high level description of the process, but most of it is left up to improvisation (see Rehnquist’s designing of his robe for the Clinton Impeachment trial.)
You better described what I was actually thinking. It’s kinda like a judge refusing to allow a jury to hear a case when the facts alleged are legally insufgicient.