R40 and unallocated space on HDD

[Béèm]

I have a R40 of which partition 1 is the ntfs one of 21.64 GB and the second the hidden rapid restore partition of 12.63 GB.

While playing with a Linux Live CD I see there is unallocated space of 2.98 GB. (used gparted for this)

So my question is, can this space be used safely or has this something to do with MBR, or is it used already for something else?