okay, I've read your post again and realised it might have meant something different.
first time around I read, "not to let it slide into fast tempo territory" as meaning that you didn't want to run them too fast. so I pointed out that they already were too fast because they are faster than tempo pace already.
however, you might also have meant that you didn't want them to slow down to tempo pace because they are meant to be faster than tempo pace.
so, then I see that you are running them off a 30% recovery, but intervals would normally be around 70% - 100% recoveries so a 5:00 repeat would have a recovery of around 3:30 - 5:00. your current recovery would seem to imply that you are, conversely, not running the repeats fast enough.
this leads to one of two conclusions:
1) these are tempos, and your comment about not wanting them to slide into tempo territory is a misunderstanding on your part of what you are doing.
2) these are meant to be somewhere between tempo and easy, say around marathon pace, which would in turn suggest that tempo pace for you is not 3:30 per km.
only you would know which of those two applies, but either one suggests to me that you need to adjust your training paces.