As to NI, yes hand it over to the EU, but the bombs will go off here.
You mean from the Unionists? Well, we will just have to do our best to prevent that, as we do with Islamic extremists in our midst. Plus, with N.I. in EU hands, we can then bring diplomatic (and if required, other kinds of) pressure to bear on the EU to control their unruly, home-grown terrorists.
Also, if the Unionists started to carry out terrorist acts in the UK, what would they hope to achieve? Readmission to the Union? Would they really be so daft as to think they could achieve that by terrorism?
And, if you think that would be the likely scenario, do you really actually want N.I. as a UK responsibility? Knowing that this is why you keep them? Foc that, ungrateful bastards.