A spare Battery

I just need a battery. My mouse I think might be broken its a doing a thing where it just scrolls, you can use it, until you open anything then it proceeds to scroll in and out, and I don't know it seems random. Or like someone else is controlling it. So I just need a battery. The fourth floor didn't have any so I ask Ray. 

Ray said he wasn't sure if they had any but proceeded to rifle through drawers. He told me the last time he ordered batteries would have been for Marta. But she is gone now, got a nice job at the CI. I guess the time before that would also have been for Eric but again he is gone now so he wouldn't know where to look. To be honest with you plenty of people come here and don't even need batteries so its a mystery why you go through so many. 

I didn't really know what to say so I stood there, and nodded. Its fine then, no worries. I mean if you have old ones I can test them as well. 

No no we'll find some, and he opened other drawers, and then maybe the same drawers and then said well lets check the second floor and there is that other spot on the fifth floor. 

Then after an hour, and a tour around the building,  I got a battery, and it was new so I was happy and put it in the mouse, casting the old one to a decommissioned tupperware. The green light turned on, great, but wait, oh no, now I can't find that the little plastic part that goes on the back.