Seems safe enough to try, except from the financial perspective of replacing any lost material. If one proton at rest is 939.9Mev, that's 1.506*10^-10 joules

Seems safe enough to try, except from the financial perspective of replacing any lost material. If one proton at rest is 939.9Mev, that's 1.506*10^-10 joules. Carrying 1*10^3 antiprotons, even if they all escaped and reacted it would just be a ~1.5*10^-7 joule event. (Unless it's doubled because of the mass of the antiprotons? I forget.)