USA's Fair Use would probably let you sample these sounds for use in developing your music even without the license.

In the UK there aren't anything like personal use exceptions so sampling if its allowed by the license would be fine, but if you play back the track and anyone hears it then strictly that's a performance and likely to be infringing (yes, UK law is that restrictive; for example UK schools have to have music performance licenses to watch TV in class in case a program includes copyright music, it's pretty ludicrous).