That’s a hard one… I can only offer a free translation to capture more or less the same meaning. Perhaps others can do better?
Isteach leat i bpáirc an áir, ní beo duit ach go dtí an cath deireannach. [Lit. Enter the battle-field, you will never feel as alive as in your last battle]
Don’t know if it really matters, but I think it should be “bhaoil” rather than “baoil”. Otherwise, excellent translation! You always hit the nail on the head, Aonghus.