Translation of "mutuor" into English

deinde intumescente motu profugus repertusque, postquam intutae latebrae, praesidium ab audacia mutuatur: non praefectum ab iis, sed Germanicum ducem, sed Tiberium imperatorem violari.

Then, when the commotion increased, he fled and having been discovered, as his hiding place was now unsafe, he borrowed a resource from audacity.