28 across: Gums capable of creating steam? (9)
The answer is messmates. I can only think there’s been a misprint somewhere, because this one seems absolutely nonsensical.
19 down: School master for the classroom, perhaps? (7)
Supposedly, the answer is anagram. Again, I’m not convinced given the clue.
25 across: Rommel’s coy reply when asked for his battle motto? (5)
The answer is Erwin, which is Rommel’s first name, but I just need confirmation that er win = coy reply when asked for battle motto.
1 down: Resign from computing? Vice versa, with facility nausea? (10)
The answer: queasiness; the explanation: missing.
15 across: Glaring back at tree knot (4)
The internet tells me that knar = tree knot, but what does that have to do with glaring back at?
4 down: In place, practically arctic outside (7)
Here, in = popular and arctic outside = polar, but what about pu and place, practically?
16 down: High school class regarding fresh salmon movements? (8)
OK, salmon movements = upstream and high = up; the rest, though?