Okay a Glint Lake:
a lake formed at the erosionally susceptible region where hard basement rocks emerge beneath a softer, sedimentary cover. Example is Lake Superior in Canada
A brain hook was an instrument used in ancient Egypt to liquefy and scoop brain out during the mummification process. (Ewww) I am not sure though if this is applicable in relation to the story. I don't remember it. Perhaps you can reference the chapter / page so that we can have a bit of an analyse regarding this.
Mummah - really don't know. Once again if you can reference the chapter / page, so that we can have a reread, would be great.