"Well...in truth...if it were just Roger and April shooting up and neither were infected, they would be fine...ok...they'd still be junkies, but you know what I mean.
There'd have to be another person involved or they had to have it before hand."
Remember in the OCR when Roger says to "the man" about Mimi "You didn't miss me, you won't miss her, you never lacked for customers". Maybe the man was involved. I don't think Mimi had anything to do with April, but the man could have been involved somehow. He obviously knows Roger from Roger's line.
"The opposite of war isn't peace, it's creation."