Even if we keep up the barrier like this, we're just waiting to die! That's why we go outside the barrier and meet the enemy head-on — got it?!
Literal
Like-this barrier [obj-を] putting-up-[even-ても] die [nominalizer-の] [obj-を] wait only is! That's-why we [topic-は] barrier [gen-の] outside [to-に] go-out-[and-て], enemy [obj-を] intercept, good [right-な]?!
Dramatic command-and-rally speech. 張っていても uses 張る ('to put up, to spread') — the standard verb for erecting magical/defensive barriers in fiction. ~を待つだけ is a fixed 'nothing but waiting' construction. 迎撃する ('to intercept, to counterattack incoming') is a military/technical verb. いいな at the end is a masculine command-agreement-seeking 'understand? got it?' — asserting the decision rather than asking permission. Stacks multiple commanding and planning structures typical of shōnen anime/RPG dialogue.