In this episode we learn that Enterprise has had a Suliban cell ship for more then a year, which may partially explain why Archer let one go in "Shockwave, part II". However, it does seem odd that Enterprise has never used this one until this point. Also, it is surprising that Starfleet Command would allow Enterprise to keep the ship instead of having it examined by an Engineering team in San Fransico. The only likely explanation is that a return trip to Earth simply to deliver the ship would be beyond impractical.