That's the hope, old quantum-tunnelflow models were able to put out greater levels of energy and quantum particles for weapons and other things, but was hard to control. The eventual hope is to combine the two models.
Well, quantum-tunnelflows don't explode, they can create massive radiation disks and worse, make black holes, but hard to do since quadruple-redundancy will prevent that.
No, since tachyon-drain reactors pose no risks. Part of the reason why it's hard to trap tachyons is that they don't interact with matter, so if they get free, nothing happens