This one didn't do much for me.
Each character was one dimensional and the language was too simple.
Becky is just TSTL--just a passing mention of the tarp and trash chute and she doesn't find that at all strange when being interviewed for a building manager position? If she had died that would just be natural selection at work.
I didn't understand the whole "has to practice so he can go faster" thing. Was that because of some mental slowness? It just came off as weird. For those who felt sorry for Becky, it's only the matter of timing for the phone call that she managed to not get her head smashed in as a practice run, so I thought it was a pretty happy ending for her.
And I don't think the final thing is even going to work. He depends on everything happening exactly as he plans it, but when she shows up in the boiler room and sees that it's him, and there's a tarp on the floor, she is not going to sit in the chair and go through an interview. She might leave, she might slap him, she might stand and argue but she's not just going to sit and docilely be interviewed like Becky did, and so his whole plan is going to fall apart. Most likely she'll get the hell out when he pulls the weapon (it is a slow SOB to swing after all) and will call the police.