This is obviously a tragedy.
It may be worth considering the privately owned weapons policies on most bases. I have never heard of a base that allowed privately owned weapons to be kept in the dorms. They generally must be stored in the unit armory, and often can only be accessed at certain times and at the discretion of the armorer (who can decide that you look drunk, depressed, etc). Some bases go further and require permission of the individual's supervisor or commander to withdraw a weapon from the armory. Furthermore all weapons must have a registration on file, and the commander usually has to sign off on the registration. Of course, carrying weapons on base is strictly prohibited and transportation must be done in accordance with strict guidelines (usually unloaded in a locked container seperate from any ammunition).
In short, it is gun control mecca: registration, pseudo-licensing (given that the gun registration is approved by the CC, who has full discretionary authority to forbid the gun from being on base at all and broad discretion over the person in question), no carrying, no storage, discretionary issue of arms from a central storage facility under supervision, and so on. Yet the suicide still occurred.
Perhaps the answer to help prevent these tragedies lies in other interventions, like timely mental health support and supportive cultures.