Sadly on July 6 2011 in update 9.1 Cipsoft revamped Rookgaard when they introduced the Rookie Guard Quest thus the training room and key 4600 was no more.The key was previously sold by Seymour for 5 gps and it was known as the key to adventure which provided access to the training room. The training room was located below the Rookgaard Academy. It contained a spider, wolf, troll, and bug which you controlled with levers in the room. The Rookie Guard Quest was meant to help players gain knowledge about the game.
I have fond memories of the training room. This is the room I'd spend hours in and I remember coming out of the room and going into a hallway that always seemed to be blocked by players. You couldn't walk through players at that time in "non-PVP" as it was called since this was before guild wars and non-PVP turning into optional PVP because of that. That's actually where I met my first game master. I don't remember the game master's name but he saved me by making the hallway get unblocked, and for that I'm forever grateful for game masters!
Taken from the news on Tibia.com dated June 22 2011-
While the world changes offer new experiences for players who have already left Rookgaard, we have also something in store for new players. After having completed the tutorial on Rookgaard, a new questline will be available which can be accepted by players up to level six. It will guide them till they reach the Isle of Destiny. Also, a few areas on Rookgaard have been revamped a bit
Sources:
https://www.tibia.com/news/?subtopic=newsarchive&id=1756
https://www.tibia.com/news/?subtopic=newsarchive&id=1749
https://tibia.fandom.com/wiki/Rookgaard_Academy