subject to -> the violence might happen
(If you're accustomed to describing your own verbs - in your own language - in terms of 'the indicative' and 'the subjunctive', that analogy may help.)
With 'the subject of', you need to express the certainty/possibility with a verb.
The bar was subjected to immense strain, but did not break.
Trains during the holiday period are subject to delay.
[This last example shows an area where you may find confusing counter-examples. Train operators often say 'may be subject to delay' when they mean 'may be delayed [because they are subject to delay]'. This sort of mealy-mouthed euphemism really makes me want to spit! ]