Amendment - comment on Bob charging round the house with glue gun -
Ooo I do hope you didn't come to a sticky end ...
Just checked my temps - and found that Cy has shed, AND eaten the mouse I'd left with her - I feed the corns when in shed but it's a red-letter day when that girl eats. Perfect shed too, with its one eyecap. Yaay!
The heat mat is normally in 2 parts, pick one of the black sections, then put the stat probe in the middle of that bit.
Put your RUB on the mat, it won't sit flat because of the stat probe but it doesn't cause any issues other than not been flat. Stick your thermometer probe anywhere in the hot end but ideally in the middle of the bit covering the heat mat. ( I did a fair bit of experimenting with probe placement over a month as I was unsure of RUBs and found that the reading isn't all that different anywhere the heat mat is so just went for near where the hot end hide would be).
Yeah it just snaps off just make sure the gun has got to full temp first. If your worried wrap a piece of cling film over the probe so it snaps away cleanly.