I think that I could do this.
Click here to view the secret text
×Does it involve a tricky passing manoeuvre to get to the other side of the Slayer?
I didn't know what triggered the Slayer's appearance so found this alternative solution. It didn't seem likely to succeed but I don't think that I have found a bug.
To complete the challenge though I need to know which eye is at (22,16) - is there one there? Is (1,1) the SW square? There are a total of 16 eyes and I could complete the room after first awakening No.8, counting from the centre.
The attached screenshot shows Beethro having passed the Slayer.