the other republicans are idiots. There are republicans on the three committees holding the hearings, they can tell the other republicans what's going on if they wish to.
Not only that, it's not the committees that are going to impeach Trump. That's going to happen in a vote by the entire House. After a period of debate and questioning.
Those Republicans will have plenty of opportunity to demand to see evidence, question people's testimony, and point out any shenanigans when they are present for the floor debates.
Hard as it is to fathom, Mr President, just because you’re the leader of the free world doesn’t entitle you to a free pass. Unfortunately, just a free press. -- Neil Cavuto