they intentionally don't let us see the floor, just the dais and the speakers.

they also be imprisoned if they leave?

That time is long past.

II. When the managers of an impeachment shall be introduced at the bar of the Senate and shall signify that they are ready to exhibit articles of impeachment against any person, the Presiding Officer of the Senate shall direct the Sergeant at Arms to make proclamation, who shall, after making proclamation, repeat the following words, viz: ``All persons are commanded to keep silence, on pain of imprisonment, while the House of Representatives is exhibiting to the Senate of the United States articles of impeachment against ------ ------''; after which the articles shall be exhibited, and then the Presiding Officer of the Senate shall inform the managers that the Senate will take proper order on the subject of the impeachment, of which due notice shall be given to the House of Representatives.

if they speak but not if they get up and leave?

The man was nice, took my name and number and said he would pass the message along.

If nothing else, it gets the point across that people are paying attention.