Maybe she wants to hold it up until they can impeach Pence. Then they can send both at once to a Dem majority in the Senate in 2021. Making her the President. In her dreams!
Interesting thought. The RATS in how they voted by simple majority to take away the rights of the minority in conducting this impeachment have completely demonstrated why the Framers established a constitutional republic, not a democracy. Having gone to that extreme, you're right, they may as well go just go full blast and impeach Pence, and while they're at it, throw in impeaching Kavanaugh for the cherry on top. They can charge Pence with aiding and abetting the obstruction of Congress and abuse of power, and they've already got a laundry list to charge Kavanaugh with. Pass a rule to make the hearing on each one day and they deliver even more goodies to their supporters for Impeachmas.
You know the hardcore ones like Mad Max and the Squad will be firmly behind it leaving just those "I looked at the evidence/I voted my conscience/blah blah" phony clymer Democrats who made a show of wringing their hands over the past few days. Why would they would draw the line now? Whatever leverage got them to go along with this charade will continue to work.