The Point is that he cant use 4 Clows and transport 4 TBB ; ) he have not so much chakra lel
It is clear as day Tobirama wasn't talking about normal teleportation otherwise Tobirama would have teleported all 4 TBB's with 4 clones but he didn't do that which is why it is safe to assume that he was talking about S/T barrier.
We can not say 100% that he is talking abou S/T barrier ^^ he say Hiraishin and nothing else