Non-story.
One Republican Senator made a comment, and some groups looking for attention made comments to get that attention. Left winger wringing his hands in an editorial about Republican "terrorists."
It's perfectly legal for the Governor in Oregon to send the State Police to get the legislators and bring them to the Capitol.
They usually don't.
The Republicans walked out over a massive gun control bill in Oregon a few weeks back. The Democrats needed a quorum for a vote on a small business revenue tax, so they killed the gun control bill, and the Republicans came back. The Democrats then passed their small business tax.
Something similar will happen this time. No arrests or shooting needed. But, if not, then it is the law in Oregon that the legislators can be forced to attend the legislative session.