In the short time that Rufus was allowed to plug in to Mac2, the machine rationalised that it must strip Rufus of all memory of the past year. That part of Rufus's internal wiring was 'parked' - temporarily put into his brain's 'recycle bin'. The boy would not be able to remember anything that he'd done or had happened. Thus he wouldn't be able to give the confession that Twigg so earnestly craved.
Twigg called time on the connection with Mac2, having seen that Rufus seemed to be recovering.
"Interesting bit of kit that!" Twigg commented, "where did you buy it?"