I would contact Toshiba and ask if they have a PDF available that shows how to open it safely. I have made contact with them in the past for other models and they have been helpful in getting back to me with a PDF that describes where the screws are located and screw types used for each hole etc.
Looking online at google I was not able to find a reference to a procedure, but that doesnt mean it doesnt exist.
On other model computers that are integrated into the display, I have found before where the base had to be removed first as for screws were hidden under the metal pivot plate.
But also in addition to screws holding it together, you may also have hidden tabs that need to be depressed to get it to open as well which you cant see, but with a PDF showing an exploded diagram of parts etc you will know where they are if there are any.