[quote=@JBRam2002]
[@The Mighty Hero] With Thieves' Tools, would I be able to roll something to jam the lock so that the gate would not be easily locked behind us once we enter? 
[/quote]

You can roll but don't necessarily have to use thieves' tools to jam the lock. For that it would either need to be a sleight of hand check or strength. I'll let you roll whichever is more beneficial for you.