Bug: Self-destruct doesn't explode excessively large core

Repro: line the mapwalls with deathmazes and attach them to a station core(didn't test with regular core) (Can supply e2 at request)
Start self destruct sequence
Cancel self destruct sequence
Start self destruct sequence
Congratulations, you now have a bugged core that won't explode

Error courtesy of Puff [ERROR] gamemodes/spacecombat2-ce/gamemode/spacecombat2/sv_main.lua:377: Tried to use a NULL entity!

1. SetAttacker - [C]:-1
2. ApplyDamage - gamemodes/spacecombat2-ce/gamemode/spacecombat2/sv_main.lua:377 3. Explode - gamemodes/spacecombat2-ce/gamemode/spacecombat2/sv_main.lua:551 4. ExplodeSimple - gamemodes/spacecombat2-ce/gamemode/spacecombat2/sv_main.lua:565 5. unknown - gamemodes/spacecombat2-ce/entities/spacecombat/plugins/core.lua:705

Timer Failed! [Simple][@gamemodes/spacecombat2-ce/entities/spacecombat/plugins/core.lua (line 702)]