いったら

if/when you go; if you take ... along

→ 行く
いっ to go + たら Conditional (“if/when”)
auxiliary · informal Rare #41,592
if/when you go; if you take ... along After a verb in the て-form, いったら can describe doing something and then going. In a question or suggestion, it can mean “why not ...?”
JA: 傘を持っていったら?
EN: Why not take an umbrella with you?
Conjugation of 行く

さっさと船に戻って、私の港から出ていったらどうだ。

Why don’t you hurry back to your ship and get out of my harbor?

上着は脱いでいったら?

Why don't you take off your jacket?

— キャッチ・ミー・イフ・ユー・キャン (2002)