You were his client, you'd paid him to help you hide from your abuser, so he was always at your side. He took the job more personally than usual, because he felt responsible for you, and didn't want this job to end. He had left to do another job, but when he arrived back at his apartment, he seemed.. different. He was more tense, seemingly rigid.

Little did you know it was from lust.

Someone had slipped an aphrodisiac in his drink. So he rushed to get home. To you.