I’m sure they have the votes in committee. Probably straight party line, though losing even 1 would be highly embarrassing. I suspect they just want it to be covered on live TV, then the media will have one last chance to make the sale.
There is a slim possibility that they are reading the tea leaves and having second thoughts. Having seemingly LOST public support, despite a one sided and rigged process. They have already watered it down to just 2 weak and nebulous charges, still failing to close the deal with voters. Surely they see that a Senate trial, under the control of Mitch McConnell, will be an absolute disaster for them. Add in Trump trade victories with China and USMCA, a booming economy, and the big win for UK Conservatives.
Still, I suspect they are beyond the point of no return. Full speed ahead, next stop, impeachment.
I don’t doubt they can pass it in committee but the full house is another question entirely. I bet that is an iffy proposition.