Shall we leave around seven just in case something happens.
Let's leave earlier around seven just in case something happens.
"余裕をもって7時くらいに出発しよう何かあったらイヤだから"
出発する leave, leave home, leave the house
７時くらい around seven, about seven
万が一 just in case
何か起こる something happens
～しよう let's, shall we?
Let's leave around seven just in case.
Shall we leave around seven just in case something happens.
Let's leave earlier around seven just in case something happens.
Let's leave around 7, with time to spare just in case something happens.
ご質問ありがとうございます。
「余裕をもって」はhave extra timeとwith time to spareと言えます。例えば、早めに到着するとarrive with time to sparetと言えます。そして、どれぐらい余裕があるかも入れることができます。
例文：Let's leave at around 7 so that we have an hour to spare.
ご参考になれば幸いです。
日本 
アメリカ合衆国 
