Needlecasting is the transference of DHF code from one sleeve to another.... you need a body to cast into.Then how (in episode 7) did our group of Envoys needlecast into a secure CTAC stronghold? Am I missing something?
More precisely, backup reinforcement sleeves. Tak said that the guard count in that facility was low, but reinforcements could be needlecast into sleeves. The Envoys could only succeed because Tak knew exactly where the backup sleeves were kept as well.