いざとなったら

expression

when push comes to shove; when the time comes; if it comes down to it

Used to express that when a critical moment or necessity arises, one will act or something will happen. Often implies a last resort or decisive moment.

• いざとなったら、私わたしが責せき任にんを取とります。

  When push comes to shove, I'll take responsibility.

• いざとなれば、彼かれは頼たよりになる。

  When the time comes, he can be relied on.