In real life an NCIS team would not try to rescue a high value asset from a trained Russian kill squad alone and without backup. They would have a REACT team backing them up, which is NCIS's tactical unit. REACT stands for Regional Enforcement Action Capabilities Training Team, they undergo the same rigorous training as special operations units like the FBI's HRT and the DEA's Spec Ops unit (in fact a lot of REACT agents are former Navy & Marine special forces) and specialize in, among other things, agent and undercover asset rescue and high-risk arrests.