Sorry to say but the first 2 terms are completely out of context in terms of what sells in .io.
Lieutenant is a bit better .. but still extremely weak for .io.
.io names need to be short, punchy and good for the tech industry.
Geography.io would likely be strong enough to get possible interest at some point, adding the "er" at the end, even if "Geographer" is a real thing, reduces both the value and demand to a fraction of a fraction.
While Lieutenant might first seem like a good choice for an online security company, it's a bit too long .. and much more importantly .. almost impossible to spell properly for the average person.
Anyhow .. good luck with these domains all the same!