Constantine was not overly concerned about Lighthouse Base.
That was merely a secondary objective in the latter half of the mission. Even though the mission required him to bring Agent Phil Coulson to meet the Emperor, it was no longer so urgent now that the Life-Model Decoy project had been secured. It would still take some time to reach Lighthouse Base by heavy truck alone. Zephyr One's advance team would be the first armed personnel to enter Lighthouse Base. Only after the Second Combat Detachment had secured Lighthouse Base and the S.H.I.E.L.D. personnel would the First Combat Detachment accompanying Constantine be able to arrive.
The Emperor had once told Constantine that most of the supplies, information, and technology he needed during the early days of his enterprise had come from S.H.I.E.L.D. and Hydra. Even if it had not been the S.H.I.E.L.D. reorganized by Howard Stark after World War II, it had still been the Brotherhood of the Shield, the spiritual origin of S.H.I.E.L.D. Everything from the City of Immortals to the three Helicarriers had been connected to them. Even the Gene Alchemy and Power Armor used to create the Praetorian Guard had partially drawn on designs from the Brotherhood of the Shield from centuries ago. Thus, every starting point of the Emperor's endeavors could be traced back to S.H.I.E.L.D.
Constantine believed the Emperor had assigned him this mission because there was something important in Lighthouse Base that needed to be retrieved. It certainly was not the Darkhold the Emperor had been seeking all along. Otherwise, the Emperor would have come to Lighthouse Base himself, bringing a large number of Gene-modded Warriors and preparing for a direct war. Constantine was certain that whatever the Emperor wanted had a lower priority than AI Aida, who had read the Darkhold. As for what