[X] She's right, rushing in would be far too risky and is unlikely to do more than get more good men killed. You'd also be putting your only lead into reaching other dimensions in direct harms way. The risk isn't work it, you'll wait until you have a significant force ready. And if it's closed by then you'll have to try again later.
[x] You have to try, if even a single person could cross and get back to tell you what is on the other side it would be an immense advantage. If you are fast about it you might even be able to rescue some of the lost team.