As @OfficialPogCat said, left click and hold just after the word do then drag your mouse to the end of the hi2 line and release the left mouse button.
Press Del or Backspace and it’ll all disappear.
You can highlight multiple lines of text at the same time with your mouse
Also if you’re using VSC and you want to remove certain text from several lines at once while leaving everything else, you can hold alt and click everything you want to select and it will have multiple cursors at the same time
you cannot edit 2+ scripts at once if that’s what you mean. You can only modify the script you currently have open. Unless you open 2 scripts at once the drag them to be next to each other (kinda like with normal application on your computer)