"You should really be checking the whole room all the time," Masozi points out. With only the teensiest flicker of resentment that he feels he's been disproportionately taking on the burden of constantly checking the room on behalf of the other students. "I'm sure you'll get better at it with practice but you should practice it before there are more mals again." 

"If there's something in there usually someone has to kill it or chase it away. Some rooms'll have more than one place you might turn things in, it's worth looking to see if there's another plausible spot, like some rooms have a lectern for some reason and you could put it in there - "

"How am I supposed to do math and also check the whole room all the time?"

"You don't have to be looking for mals literally all the time, just do a quick check every problem or every few minutes. It can be kind of tricky to find the right balance, if you check too much you miss what's going on in class, if you don't check enough - well you won't know you weren't checking enough until you do know and then you're in trouble. You'll get better at doing it quickly over time."