Plot hole: Those people created for medical experiments cannot run. In fact they can barely walk, so how come they can climb nearly as fast as Rose? What's more, when you see them climbing, they seem to have little ability to coordinate hand over hand. Even with the delay brought on by the cat-woman-thing, they should not have been able to keep up with her.
Plot hole: The Sycorax begin speaking English for all of the humans because the TARDIS is suddenly activated when the Doctor wakes up. However, it is stated elsewhere in the series that the TARDIS only translates for those who have been in the TARDIS, which Harriet and her translator haven't.