It seems a very likely strategy for Comey (based on past instances of him lying under oath) to have tasked the unit with breaking into the phone, then simultaneously pushing on Apple to unlock it.

In this scenario, all Comey had to do was NOT ACCEPT the final report from the unit working on the phone, and that project would remain at <100% indefinitely. In a military beaurocracy setting, until a work order or transfer order is signed off by the one who issued it, it is not legally binding as being completed. Also, easy for Comey to tell the unit not to contact him with any details so he wouldn't have to purjure himself.

In any case, he really should be in jail, as he is a total sociopath and all of those FBI guys are guilty of watching kiddy porn.