When Mandalore's boys storm the Ravager, he and Kex take a little stroll. Mandalore asks Kex if the Republic will suspect their explosives.

 

What do they mean?

Why would they worry about that?

I'm pretty sure they're referring to the proton cores you're planting all over the Ravager. I'm not certain why they're worried about the Republic, but my guess is they just want to make sure they can slip away after the battle. If the Republic knew there was a large group of Madalorians still out there who had access to high-grade explosives capable of destroying a ship that size, Mandalore's secret little camp could get into some trouble.

Yep. He wants them to build up unsuspected.

Moving to Spoilers.

For Mandelore! What ever the reason, you can markup another one for the Mandelorians. We know how the Raveger turned out.