When Boss heard those words at the time, he felt challenged. Boss dismissed Don, not because there were no positions, but because of the face, Don had. It was like Don didn't care about anything, and it even further increased his thoughts when Don walked away without another word. April knew what Boss thought because she had seen that look all day. The look of someone who thought Don wasn't good enough for their company.
As such, Boss called out to them, "Wait! Do you think he can handle this? Alright, I'll give him two weeks. If he doesn't meet expectations, he's fired." Boss said, mostly directed at April, who smiled then looked up to Don. "There we go. Good luck, darling~ I'll be waiting." April then released Don and skipped to the lobby to relax and wait while Don went to the back and did as Boss instructed.