I'm not sure the Big 4 TCs are really in-house - an in-house role will involve addressing the legal needs of the company at which you work. Big 4 training is, much like at a law firm, providing legal services to external clients. I would in many ways consider gov't TCs more in the vein of in-house work.Not sure if they have training contracts but it would still be in-house by virtue of not being a firm or government legal scheme.