In a fictional context, one possible reason Messenger would instruct Gram to hide in his Underwater Base to avoid Prince Veker could be that Prince Veker poses a significant threat or danger to Gram. Messenger might believe that the Underwater Base is a secure location, offering protection due to its hidden nature and the challenges associated with navigating underwater environments.
Messenger might also be aware of Prince Veker's motives—perhaps he is seeking something from Gram, or he wants to confront him over a past conflict. The Underwater Base could serve as a strategic retreat, allowing Gram to regroup and plan his next move without the immediate pressure of Veker's presence.
Additionally, the underwater setting could provide unique advantages, such as advanced technology, resources, or even allies who can assist Gram in his time of need. Ultimately, Messenger's advice to hide there may stem from a combination of a desire to protect Gram, a tactical decision based on the risks posed by Veker, and the unique attributes of the Underwater Base itself.