Based on the prompt: I read Payment, and for some reason, I can see other characters carrying Zak in a bag too, like the Beeman guy and the Epsilon guy from the Saturdays' Secret Scientist club.
.
.
.
Arthur didn't do nervous. Or most emotions, really. It was for the best. He couldn't have become an expert on aliens if he had to deal with distractions and liabilities like surprise, love, and guilt.
Gross.
However... he thought that nervous might feel something like this. Only more so. Definitely more so. Because he was not nervous.
The duffle bag he'd slung over his shoulder twitched.
Crud.
Had he screwed up the dose? Ugh, that was just peachy.
But the bag settled again, and the people around him were none the wiser. He let out a breath. Not in relief, because, again, emotions, but because exhaling was the natural follow-up to inhaling.
He got off the bus and walked down the street. Now, if he was remembering correctly, and he always did, the building he was looking for was- Aha! Here it was. God, it had been years since he'd been to this dump.
Once up the stairs and in the door he let out another breath of not-relief. Really. He was just breathing.
Hardly anyone knew this about this place. It had belonged to his grandfather, way back. Arthur had kept it because, well, in his line of work, it paid to be prepared. For anything. Including colleagues turning on him.
Bolt holes and safehouses were necessary.
He climbed down into the basement. He was glad he'd retrofitted it for research. And containment.
After all, something that could hold an alien enemy of unknown abilities could hold a cryptid. Even if that cryptid was the reincarnation of Kur.