I have an easier method.
1. Special forces are dispatched for multiple breakout attempts
2. extremely violent reprisals are indiscriminately committed against gnomes with continuous demands for release or else the violence will escalate
3. thousands of tons of napalm are dropped on gnome cities
4. nuclear forces are put on high alert
ᴵ ʷᶦˡˡ ⁿᵒᵗ ˡᶦᵉ, ʸᵒᵘʳ ᶜʰᵃⁿᶜᵉˢ ᵒᶠ ˢᵘʳᵛᶦᵛᵃˡ ᵃʳᵉ ᵠᵘᶦᵗᵉ ˢˡᶦᵐ